Changes to support FHS paths.  Fairly hacky cwd-based implementation
Makefile: add PREFIX and DESTDIR
Add 'uninstall' Make rule
Data installation script 'install.py' for make install
Fix Makefile prefices (from akien-mageia)
Merge branch 'fhs'

Conflicts:
	harris.c
Add TClass icons to intel_targets
Add greyed-out intel button for when target (or bomber) intel text is missing
Slightly improve TClass Radar icon