Remove CONTIRIBUTION.md

[hyrodium]

I propose removing the file for the following reasons:

• It is incomplete.

To start hacking code or writing docs, simply:

1. julia> Pkg.add("Quaternions"); Pkg.checkout("Quaternions")
2. ???
3. Profit Share with the world!

• Some URLs are out-of-date. (e.g. http://docs.julialang.org/en/release-0.2/manual/packages/?highlight=pkg#package-development)

• I think we don't need the file since the way of contribution is the same as other Julia packages.

[codecov]

Codecov Report

Merging #83 (5c01feb) into master (4cf7f2d) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #83   +/-   ##
=======================================
  Coverage   97.21%   97.21%           
=======================================
  Files           3        3           
  Lines         395      395           
=======================================
  Hits          384      384           
  Misses         11       11           

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[sethaxen]

Agreed!