[llvm-rc] Add MENU parsing ability (parser, pt 4/8).

This extends llvm-rc parsing tool by MENU resource
(msdn.microsoft.com/en-us/library/windows/desktop/aa381025(v=vs.85).aspx).
As for now, MENUEX
(msdn.microsoft.com/en-us/library/windows/desktop/aa381023(v=vs.85).aspx)
seems unnecessary.

Thanks for Nico Weber for his original work in this area.

Differential Revision: https://reviews.llvm.org/D36898

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@311956 91177308-0d34-0410-b5e6-96231b3b80d8
10 files changed