#1 Installer/excecutable improperly split

[Jake Mannix]

When running the FreeMess-0_1_0.jar, it assumes it is
installing if it is not run with --dir set to the
directory it is supposed to install into.

Fix: have the installer test what system type it's
running on, and set up .bat/.sh/.whatever files to be
used as the shortcut to run the app, and put the jar
file in the FreeMess/ directory.

Current workaround: either use the default install
directory, or run with --dir freemess_dir.