hash function callback to _.memoize() can have any number of arguments
fix overriding comparator for Backbone

having the "sort" version of the comparator return a number, while technically correct according to the Backbone documentation, does not actually work when the "sortBy" version of the comparator is used.
Merge pull request #859 from ashwinr/master

hash function callback to _.memoize() can have any number of arguments
Add support for d3's tickPadding and tickValues functions.
Add support for d3.round to D3.Base
Merge pull request #862 from michaelgmiller/master

Add support for tickPadding, tickValues, and round
Update definition and tests for pickadate.js v3.2.0
Reuse shared properties in pickadate.js definition