Add kalimba as a platform.

This change comprises of additions and some minor changes in order that
"kalimba" is listed as a supported platform and that debugging any
kalimbas results in PlatformKalimba being associated with the target.

The changes are as follows:

* The PlatformKalimba implementation itself
* A tweak to ArchSpec
* .note parsing for Kalimba in ObjectFileELF.cpp
* Plugin registration
* Makefile additions

Change by Matthew Gardiner

Minor tweak for cmake and Xcode by Todd Fiala

Tested:
Ubuntu 14.04 x86_64, clang 3.5-built lldb, all tests pass.
MacOSX 10.9.4, Xcode 6.0 Beta 1-built lldb, all tests pass.

llvm-svn: 213158