investigate c++ module implementations

[pkoretic]

there is work on c++ module system

proposal from microsoft (available in visual studio - info):

• http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4465.pdf
• https://isocpp.org/files/papers/p0143r0.pdf

work from llvm:

• http://clang.llvm.org/docs/Modules.html
• http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/