Added a "sources.py" which adds a command that can print out the source files...

Added a "sources.py" which adds a command that can print out the source files contained in one or more modules.

Added "mach_o.py" which is a mach-o parser that can dump mach-o file contents and also extract sections. It uses the "file_extract" module and the "dict_utils" module.

llvm-svn: 189959