Improvements to the Register Allocator

[tgiphil]

Avoids register spills to stack in certain use-cases (#80), and better register selection.

Results:

• 27% less spill to the stack
• 3% less register moves

Also include fixes register size issue when inlining methods.

Fixes: https://github.com/mosa/MOSA-Project/issues/1141

[tgiphil]

Sorry; lots of code clean up and package updates as well.