VisualC++ Project Missing Include Dirs and ZLIB Compile Issue

[windsurfer1122]

• The VS projects are missing the project include dir "$(ProjectDir)..\libb64" for cdecode.h and cencode.h, which belongs directly to the project only.

• The platform directories are also not in the git repository. Either add them directly or mention them in the docs. Also add to the docs that for VC++ the includes (zlib.h, zconf.h) and compiled library (zlibstat.lib) have to go inside ./platform/win[32|64]/[include|lib] respectively.

• For Visual C++ also add the note that ZLIB has to be compiled without the ZLIB_WINAPI definition, otherwise there are link errors LNK2001.