Arcane Blade Rework

This is an attempt to make the base Arcane Blade class more interesting as well as balanced.

The changes in b35 and onwards with the saving throws, physical power, spell power, and mind power hit the Arcane Blade particularly hard in terms of damage output in what might be considered a classical way to play with it.

This addon provides many more tactical options for the Arcane blade by introducing elemental melee trees and stances. It also tries to make dual-wielding, two-handed, and sword-and-board equally appealing.