Simple maintenance improvements (#1918)

* Use license file from gnu.org

Downloaded from:
https://www.gnu.org/licenses/gpl-3.0.txt

* Add missing final newline

* Fix link

* Fix shellcheck warnings

* Move donation header one level up

* Fix typos

* Stop mixing tabs and spaces

* Trim trailing whitespace

.github/workflows/Linux-pack.yml

@@ -2,7 +2,7 @@ name: Packaging(Linux)
 
 on:
   push:
-    branches: 
+    branches:
       - master
     paths-ignore:
       - 'README.md'
@@ -37,13 +37,13 @@ jobs:
               os: debian,
               symbol: buster,
               arch: amd64
-            }          
+            }
           - {
               name: debian-10,
               os: debian,
               symbol: buster,
               arch: arm64
-            }       
+            }
           - {
               name: debian-10,
               os: debian,
@@ -55,13 +55,13 @@ jobs:
               os: debian,
               symbol: bullseye,
               arch: amd64
-            }          
+            }
           - {
               name: debian-11,
               os: debian,
               symbol: bullseye,
               arch: arm64
-            }       
+            }
           - {
               name: debian-11,
               os: debian,
@@ -75,7 +75,7 @@ jobs:
               arch: amd64
             }
     steps:
-      - name: Enable Docker Experimental Features 
+      - name: Enable Docker Experimental Features
         run: |
           echo $'{\n  "experimental": true\n}' | sudo tee /etc/docker/daemon.json
           mkdir -p ~/.docker
@@ -115,7 +115,7 @@ jobs:
       - name: Checkout Source code
         if: github.event_name == 'push'
         uses: actions/checkout@v2
-        with: 
+        with:
           fetch-depth: 0
           ref: master
       - name: Checkout Source code
@@ -324,7 +324,7 @@ jobs:
       - name: Checkout Source code
         if: github.event_name == 'push'
         uses: actions/checkout@v2
-        with: 
+        with:
           fetch-depth: 0
           ref: master
       - name: Checkout Source code
@@ -438,7 +438,7 @@ jobs:
       - name: Checkout Source code
         if: github.event_name == 'push'
         uses: actions/checkout@v2
-        with: 
+        with:
           fetch-depth: 0
           ref: master
       - name: Checkout Source code
@@ -484,7 +484,7 @@ jobs:
             openssl \
             ca-certificates
       - name: Get go-appimage tool
-      # Will not use linuxdeployqt anymore, because it suopprts currently still-supported mainstream distribution, 
+      # Will not use linuxdeployqt anymore, because it suopprts currently still-supported mainstream distribution,
       # which is glibc 2.23. For more information, please see https://github.com/probonopd/linuxdeployqt/issues/340.
       # Will try new tool https://github.com/probonopd/go-appimage written in golang by probonopd.
         run: |
@@ -614,7 +614,7 @@ jobs:
       - name: Checkout Source code
         if: github.event_name == 'push'
         uses: actions/checkout@v2
-        with: 
+        with:
           fetch-depth: 0
           ref: master
       - name: Checkout Source code

.github/workflows/Windows-pack.yml

@@ -62,7 +62,7 @@ jobs:
       - name: Checkout Source code
         if: github.event_name == 'pull_request'
         uses: actions/checkout@v2
-        with: 
+        with:
           fetch-depth: 0
           ref: ${{ github.event.pull_request.head.sha }}
 

.github/workflows/build_cmake.yml

@@ -32,7 +32,7 @@ jobs:
       - name: Checkout Source code
         if: github.event_name == 'pull_request'
         uses: actions/checkout@v2
-        with: 
+        with:
           ref: ${{ github.event.pull_request.head.sha }}
 
       - name: Install Dependencies
@@ -62,10 +62,10 @@ jobs:
         # access regardless of the host operating system
         shell: bash
         working-directory: ${{runner.workspace}}/build
-        # Note the current convention is to use the -S and -B options here to specify source 
-        # and build directories, but this is only available with CMake 3.13 and higher.  
+        # Note the current convention is to use the -S and -B options here to specify source
+        # and build directories, but this is only available with CMake 3.13 and higher.
         # The CMake binaries on the Github Actions machines are (as of this writing) 3.12
-        # 
+        #
         # We need to source the profile file to make sure conan is in PATH
         run: |
           cmake $GITHUB_WORKSPACE -DCMAKE_BUILD_TYPE=$BUILD_TYPE
@@ -78,7 +78,7 @@ jobs:
       - name: Test
         working-directory: ${{runner.workspace}}/build
         shell: bash
-        # Execute tests defined by the CMake configuration.  
+        # Execute tests defined by the CMake configuration.
         # See https://cmake.org/cmake/help/latest/manual/ctest.1.html for more detail
         run: ctest -C $BUILD_TYPE
 

.github/workflows/clang-format.yml

@@ -13,7 +13,7 @@ jobs:
     - name: Checkout Source code
       if: github.event_name == 'pull_request'
       uses: actions/checkout@v2
-      with: 
+      with:
         ref: ${{ github.event.pull_request.head.sha }}
     - uses: DoozyX/clang-format-lint-action@v0.9
       with: