Word War vi

The makefile was modified to allow cross compilation so that Word War vi can run on OpenPandora. The default explosion shape was changed from rectangular to round.

New enemies, Tesla towers and Gunwheels, were
added to later levels. The difficulty of levels
was tweaked to try to make the increase in
difficulty ramp up more smoothly and gradually.
Cosmetic improvements were made to the appearance
and motion of the Space Octopi. The duration of
Xbox 360 controller rumble effects was shortened
to 1/4th of a second to make the effects correlate
more sharply with the events which cause them.

The Space Octopi now have frickin' lasers on their heads. Stallman's airships now have frickin' lasers as well. A bug where portaudio was being shut down prematurely has been fixed. Some items no longer simply disappear upon being shot, but instead leave behind destroyed wreckage.

"xmas mode" was added in which you not only get to
blow stuff up and rescue your buddies, as usual,
but you get to do so while piloting Santa's sleigh
and delivering presents.

The "--thicklines" option was added, which causes
everything to be drawn with thicker lines. Icons
were added. Minor optimizations were made for
performance. The Linux specific rumble code was
protected with ifdefs. Now bombs bounce off the
airships.