backbone.shard: add partition() and chunk()

tests: Underscore 1.9.1

tests: QUnit 1.23.1

demo: jshint caught me

js: enforce current code style

js: use === where appropriate

backbone.shard: update copyright years

tests: move some test to another, more appropriate, section Too many methods that allow searching/filtering were put into "basic" category.

docs: reword overview and usage a bit

backbone.shard: add new methods (from Underscore), test them Namely, these methods are added: - difference - findIndex - findLastIndex - includes - sample