This patch adds a new field to the state templates. If this extension
field is != 0, then the line is only applied to the final state table
if the extension is supported. Once a line is applied to the final
table, all further templates for this state from the same pipeline
part are ignored. This allows removing some extension checks from the
state handlers, which cleans them up and saves a few CPU cycles when
applying the states.

Also fixes the range on the test, 0x19 plus 1 equals 0x1a, and
0x003c0000 should've been 0x004c0000.

Slightly improves readability.

Also removes now redundant setting of vidmem flag on rendertargets, prevents 
adding vidmem flag when sysmem flag is present. Fixes missing textures in Forsaken.