primed grenade indicators.
fix builder error question mark.

also an unused var that's been nagging me.
smooth out grenade flashing
colourize numbers and shift positions
adjustments
fix xp thing
define UFO fuel in ruleset

because USOs use Zrbite
some TFTD infrastructure

slightly more dynamic loading of graphics, function for loading palettes from lbm files

horrendous hard coding in place here, disassociating surface names from file names

sprite recolouring disabled for aquanauts for the time being.
add depth to battlescape

please note: TFTD is still not supported.