If you are using VS2015 then warnings are expected. VS2015 compiler warns about new stuff that Casey doesn't see on the stream - he is using VS2013.
Fixing warnings can be made easier by "hiding" them with compiler flag it tells you in the output log (/Wv:18). But it won't solve all warnings. Those which will be left you'll need to fix it or downgrade to VS2013.
As for META_HANDLE_TYPE_DUMP, it is defined in handmade_generated.h But because build of simple_preprocessor.exe failed, the build.bat file overwrote handmade_generated.h file (it should be empty for you now). So don't worry about this error. First fix everything so simple_preprocessor.exe builds successfully, and then you'll get correct handmade_generated.h file (or simply extract it from zip file if you want to see how it looks now).