[Ohrrpgce] SVN: teeemcee/10925 Add xy_position_on_sprite_slice, use it in attack and enemy editors for

[subversion at HamsterRepublic.com]

teeemcee
2019-01-18 18:44:10 -0800 (Fri, 18 Jan 2019)
238
Add xy_position_on_sprite_slice, use it in attack and enemy editors for slightly nicer positioning

As a bonus, I could delete some ugly code in the enemy editor for temporarily
coercing the enemy preview slice to the center of the screen
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U   wip/attackedit.bas
U   wip/customsubs.bi
U   wip/customsubs.rbas
U   wip/enemyedit.bas
U   wip/slices.bas
U   wip/slices.bi