Merge pull request #21 from ricemery/rna-transcription

Add rna-transcription exercise
Add triangle exercise
Merge pull request #22 from ricemery/triangle

Add triangle exercise
Add binary exercise
Merge pull request #23 from ricemery/binary

Add binary exercise
Added roman-numerals exercise
Merge pull request #24 from ErikSchierboom/roman-numerals

Added roman-numerals exercise.

Thanks
Add prime-factors exercise
Merge pull request #25 from ricemery/prime-factors

Add prime-factors exercise
Simplify example
Merge branch 'master' of https://github.com/exercism/xscala into rna-transcription