Tutorial scenery

Adds the Tutorial Plant, a decorative object for the revamped tutorial map.

Also adds two new actions: A_StateRangeByAngle and A_StateRangeByParameter, which will change an object's state to a state from a specified range (using var1/var2 as the lower/upper bound), depending on its angle or parameter/extrainfo value. These actions were used by the SOC prototype of the tutorial plant, to manually change the starting point of their animation. While the actions ended up unused, they might be useful for custom objects, so I've left them in.

(based on next, beware save files) srb2win_tutorialplant.exe tutorialplant.wad