Working Exception and AnyException

[danielpclark]

I believe this is good to go except for most of the documentation was copied from the Ruby doc. So I'll likely need to revise it. I don't mind if you merge it. This doesn't effect any current systems, implementations, or behavior.

The full_message method is commented out as it would cause a panic if used as is. In Ruby it outputs:

"\e[1mTraceback \e[m(most recent call last):\n(irb):10:in `full_message': \e[1msomething went wrong (\e[4;1mStandardError\e[m\e[1m)\n\e[m"

TODO

• Update documentation
• Add alternative to raise for rb_exc_raise which works best with this.
• Wait for ruby-sys update and update Cargo.toml