Refactor Float implementation

[mattico]

#166 refactored the integer intrinsics by:

• Adding wrapping_ functions to the Int trait, removing the need for lots of Wrapping(x) and x.0
• Using traits to implement the various operations rather than using macros

These can both be applied to some extent to the floating point implementation.

[mattico]

I created this issue as a reminder for myself, so I'll get around to doing this eventually.