Fix a typo and add syntax highlighting language

`poweful` → `powerful`

README.md

@@ -13,7 +13,7 @@ tinyobjloader
 
 http://syoyo.github.io/tinyobjloader/
 
-Tiny but poweful single file wavefront obj loader written in C++. No dependency except for C++ STL. It can parse 10M over polygons with moderate memory and time.
+Tiny but powerful single file wavefront obj loader written in C++. No dependency except for C++ STL. It can parse 10M over polygons with moderate memory and time.
 
 `tinyobjloader` is good for embedding .obj loader to your (global illumination) renderer ;-)
 
@@ -88,7 +88,7 @@ Usage
 -----
 
 TinyObjLoader triangulate input .obj by default.
-
+```c++
 #define TINYOBJLOADER_IMPLEMENTATION // define this in only *one* .cc
 #include "tiny_obj_loader.h"
 
@@ -151,10 +151,10 @@ TinyObjLoader triangulate input .obj by default.
   }
   printf("\n");
 }
-
+```
 
 Reading .obj without triangulation. Use `num_vertices[i]` to iterate over faces(indices). `num_vertices[i]` stores the number of vertices for ith face.
-
+```c++
 #define TINYOBJLOADER_IMPLEMENTATION // define this in only *one* .cc
 #include "tiny_obj_loader.h"
 
@@ -191,3 +191,4 @@ Reading .obj without triangulation. Use `num_vertices[i]` to iterate over faces(
   }
 
 }
+```