Move Hangul Syllable composition and decomposition to [unic-ucd-hangul]

[eyeplum]

Implement #209

[eyeplum]

Thanks for the review @behnam! I have updated the PR according to the suggestions. Also added a simple README.md file.

[behnam]

bors: r+

[bors[bot]]

Build succeeded

• continuous-integration/travis-ci/push