glossmap textures are now brighter (no change to forced gloss brightness)

glossmap textures are now brighter (no change to forced gloss brightness)
now clears lights when reloading lights
r_editlights_quakelightsizescale cvar added, default 0.8, controls size of lights imported from maps, gets a major speed gain but makes the map a little darker
R_Shadow_NewWorldLight now checks if radius or color is too dim and won't spawn such lights
in editing mode the centers of lights are visible now (as crosshair images)
light selection is now done a bit differently - the more precisely you point at a light, the higher it's rating gets, sometimes surpassing the closer lights in the area

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@2609 d7cf8633-e32d-0410-b094-e92efae38249