Added Set
Merge pull request #42 from aochagavia/set

Added Set
Fixed comments on set.rs
Add Gitter chat link.

Might as well try it!
Fixed almost_prime.rs
Fixed anagrams.rs
Fixed averages_mean_angle.rs
Added 'implements [link]' to all files
Merge pull request #43 from aochagavia/comments

Added 'implements [link]' to all files
Added implementation of Stack
Fixed LZW compression
Fixed markov algorithm
Fixed prime decomposition
Fixed sieve of eratosthenes
Merge pull request #45 from aochagavia/stack

Added implementation of Stack and fixed compile errors
Improved almost_prime.rs and added tests
Improved arithmetic integers
Improved arithmetic_mean and added tests
Merge pull request #47 from aochagavia/pr

Added some tests and cleaned a bit
Updated readme.