[Ohrrpgce] SVN: james/8551 Clean up perform_npc_move() refactoring the collision detection for wall

[subversion at HamsterRepublic.com]

james
2017-03-17 12:48:56 -0700 (Fri, 17 Mar 2017)
389
Clean up perform_npc_move() refactoring the collision detection for walls, zones, hero, and other npcs
into the new npc_collision_check() function which can be used in other places (for example, new movement types)

Haven't decided yet whether to expose a plotscripting interface towards this, leaning towards
yes, but don't want to interfere with future non-tile-algined movement support
---
U   wip/game.bas