Add basic TOML support

WIPS:

- Multiline Arrays (https://github.com/mojombo/toml#array) aren't working
- "double comments" (# foo # bar) aren't working
- `Lexer#guess_by_source` can't properly differentiate between INI and TOM

For more info about TOML see: https://github.com/mojombo/toml¬
Fix Comment issue
Fix multiline arrays
Fix source guessing
Merge branch 'toml' from coffeejunk/toml