Added new OptionGroup classes for UInt64, UUID, File and Boolean values.

Removed the "image" command and moved it to "target modules". Added an alias
for "image" to "target modules". 

Added some new target commands to be able to add and load modules to a target:
(lldb) target modules add <path>
(lldb) target modules load [--file <path>] [--slide <offset>] [<sect-name> <sect-load-addr> ...]

So you can load individual sections without running a target:

(lldb) target modules load --file /usr/lib/libSystem.B.dylib __TEXT 0x7fccc80000 __DATA 0x1234000000

Or you can rigidly slide an entire shared library:

(lldb) target modules load --file /usr/lib/libSystem.B.dylib --slid 0x7fccc80000

This should improve bare board debugging when symbol files need to be slid around manually.

llvm-svn: 130796