Add new power-type parameters to be used in SpellInfo().

Add new power-type parameters to be used in SpellInfo().

- Make the "buff no cost" and "buff half cost" parameters power-specific.

  The new parameters are now:

    buff_<powerType>_none, e.g., "buff_chi_none", "buff_focus_none", etc.
    buff_<powerType>_half, e.g., "buff_energy_half", etc.

- Add "min_<powerType>" parameter for minimum resource requirements.

- Add "max_<powerType>" parameter for maximum resource requirements.

  For example, a holy power "finisher" denoted by holy=0 can be capped at
  using a maximum of 3 holy power.

- Teach state:PowerCost() to properly return the cost of a "finisher"
  spell that consumes all (or some variable portion) of the resource.

git-svn-id: svn://svn.curseforge.net/wow/ovale/mainline/trunk@1301 d5049fe3-3747-40f7-a4b5-f36d6801af5f