dimensioned 0.6.0

Compile-time dimensional analysis for various unit systems using Rust's type system. Dimensioned aims to build on Rust's safety features by adding unit safety with no runtime cost. In addition, it aims to be as easy to use as possible, hopefully making things easier for you not just by avoiding bugs but also by making it clear what units things are. Never again should you need to specify units in a comment!
Documentation
# To do
- Blog :: Write post about history of dimensioned?
- Doc :: Rewrite docs as well as website tutorial
- Examples :: Monte Carlo w/ and w/out units
- Readme :: Write extensive readme

- Convert :: impl From
- test all ops extensively if possible
add constant block to mscro, finish unit systems

# Questions
- What all derived types should be generated? Do with build script or just macro?
- What unit systems to include? Definitely si and cgs. fps? An imperial si alternative? Does one
  exist?

# Future
- OIBIT :: Once opt-in built-in traits stabilizes, we can deprecate the feature and add it to beta
           / stable

- on_unimplemented :: Once this stabilizes, we can try try to make error messages better.

- Numerics :: If and when Rust supports numerics and arithmetic in type signatures, switch to using
              them instead of typenum. This is almost certainly in the far future.

- Serialize / Deserialize

# Known Bugs