Fix 220: Create plural module

Borrow santhoshtr/CLDRPluralRuleParser.

Ref #220

- [x] Implementation (basically a wrapper);
- [x] Unit tests;
- [x] Build;
- [x] Functional tests;
- [x] Docs;

I'd group the locale variables and have `fakeFormatValue` at the start or end. Right now its now even alphabetic.