Package for npm

This commit does a number of things: 

- Uses RequireJS for browser
- Updates Node module for AMD
- Updates node tests and browser tests
- Packages for npm publishing
- Adds examples for both node and browser
- Merges some bug fixes from @mahnunchik
- Updates README to reflect these changes

Module is also now available on npm as `lucene-query-parser` (https://www.npmjs.org/package/lucene-query-parser).