Make clean on MinGW-W64 batch.

Add notes to readme for how to swap to C++ or use your own code.

README.md

@@ -62,6 +62,12 @@ The built code will be in the bin dir
 # Working directories and the resources folder
 The example uses a utility function from path_utils.h that will find the resources dir and set it as the current working directory. This is very useful when starting out. If you wish to manage your own working directory you can simply remove the call to the function and the header.
 
+# Changing to C++
+Simply rename src/main.c to src/main.cpp and re-run the steps above and do a clean build.
+
+# Using your own code
+Simply remove src/main.c and replace it with your code, and re-run the steps above and do a clean build.
+
 # Building for other OpenGL targets
 If you need to build for a different OpenGL version than the default (OpenGL 3.3) you can specify an openGL version in your premake command line. Just modify the bat file or add the following to your command line
 

build-MinGW-W64.bat

@@ -1,4 +1,5 @@
 cd build
 premake5.exe gmake2
-pause
-cd ..
+cd ..
+make SHELL=CMD clean
+pause