ENYO-690: Converting to a more functional style. Adding initial documentation.

### Issue
There was little to no documentation for the `resolution-independence` LESS plugin.

### Fix
JSDoc-style documentation has been preliminarily added, though it is still a bit rough. Also further optimized the code.

Enyo-DCO-1.1-Signed-off-by: Aaron Tam <aaron.tam@lge.com>