Adds the optional 'speed' field to talents, which will change how much energy they use.
Adds the optional 'display_speed' field to talents, which will change what is displayed under 'Usage Speed' in the talent description.
The default 'Usage Speed' line in the talent description displays the speed type and the % of a turn it will use, accounting for the actor's current speed bonuses. (eg. "Usage Speed: Spell (100% of a turn)", or "Usage Speed: Weapon (90% of a turn)" with a 'quick' weapon.)
Changed a few talents that don't use any speed to use one. (Dirty Fighting, Ambush tree)