mint-arena: Delete the engine files
mint-arena: update Makefile and travis
Merge remote-tracking branch 'mint-arena/master'

Conflicts:
	ChangeLog
	Makefile
	README.md
	code/botlib/be_interface.c
	code/renderercommon/tr_font.c
	make-macosx-ub.sh
	make-macosx.sh
	misc/nsis/Makefile
	misc/nsis/ioquake3-q3ctc.nsi
	misc/nsis/ioquake3.nsi.in
	misc/quake3.icns
	misc/quake3.ico
	misc/quake3.svg
ebx: Remove remaining icons

The mac folder icon (for Turtle Arena) was never used.
The quake3-tango.svg is the window icon (in data repo) with a drop shadow.