Release

This includes a number of fixes/improvements. This version of the installer should be distributed by itself, the python script will automatically download required sources.

-Auto detection of previous LLVM builds -> will not rebuild unless desired
-Auto detection of previous PyYaml builds -> will not rebuild unless desired
-Updating command line argument parsing to use the Python standard argparse module
    -Automatically generate usage, --help, and 'unknown argument' messages.
-Installer automatically downloads required source files
-Installer builds to current directory, instead of sub directories

use "python InstallLLFI.py -h" to see all command line arguments.

Not yet implemented: full support for OSX GUI building.