[llvm-rc] Serialize DIALOG(EX) to .res files (serialization, pt 4).

This is now able to serialize DIALOG and DIALOGEX resources to .res
files. It still can't parse dialog-specific CAPTION, FONT, and STYLE
optional statement - these will be added in the following patch.

A limited set of controls is included. However, more can be easily added
by extending SupportedCtls map defined in ResourceScriptStmt.cpp.

Differential Revision: https://reviews.llvm.org/D37862

llvm-svn: 314578