Initial commit of LLDB Machine Interface Frontend.

- Tested with Eclipse, likely to work with other GDB/MI compatible GUIs.
- Some but not all MI commands have been implemented. See MIReadme.txt for more info.
- Written from scratch, no GPL code, based on LLDB Public API.
- Built for Linux, Windows and OSX. Tested on Linux and Windows.
- GDB/MI Command Reference, https://sourceware.org/gdb/onlinedocs/gdb/GDB_002fMI.html

llvm-svn: 208972