1) added checkmove forward so it's easier to build against walls
2) Can't build sentries on top of forcefields anymore (they get bounced off)
3) fieldgens are now one unit taller than their fields, so you CAN build on the gen
4) forcefields bounce everything (including buildings) away now.
5) added #ifdef DISALLOW_BLOCKED_TELE around tele block checks. didn't get the point
Debug tweaks:
1) added #ifdef DEBUG, which enables RPrint(), dremove(), and printtrace(), as well
as the warlock cheat and origin reporting.
2) replaced EVERY dprint with RPrint.
3) changed makefile so that all = no DEBUG and no .sym