BUG: change README, to be copy and paste friendly

README.md

@@ -10,8 +10,8 @@ Another attempt to do something with OpenGL
 
 ## Build
 ```bash
-$ mkdir build
-$ cd build
-$ cmake .. -DCMAKE_BUILD_TYPE=Debug -DCMAKE_EXPORT_COMPILE_COMMANDS=true
-$ make
+mkdir build
+cd build
+cmake .. -DCMAKE_BUILD_TYPE=Debug -DCMAKE_EXPORT_COMPILE_COMMANDS=true
+make
 ```