Core/Player: Correcting Mana Power regeneration, for cataclysm.

- Adjusted Mana Power regen, to properly scale with Spirit
- Seems StatSystem was Updated with the Removal of MP5,
- but the power was still regenerating at the same rates,
- for most casters /Oom = dead.
- still threading through core, to remove, and correct this issue.
- mana is returning now, but it not at the right rates.(incombat/Ooc)

MP5 was removed removed from wow in patch 4.0.1.and replaced with Spirit.
Check http://www.wowwiki.com/Mana_regeneration for the detailed mechanics
of mana regen.

Signed-off-by: bootz <bootz@projectskyfire.org>