Add support for IceCube::Rule.until

Add an extra input that takes a date in user-specified format that can
be specified using RecurringSelect.date_format= (defaults to :db format
%Y-%m-%d). Add jQuery UI as a dependency for the datepicker.
Move datepicker_format into an option on the form helper

The format can be passed as the :until_datepicker_format option on the
form helper or a data-until-datepicker-format html option. The
until_time will be passed between the server and frontend using the unix
timestamp.
Merge branch 'until_time_input' of git://github.com/mhchen/recurring_select

Conflicts:
	app/assets/javascripts/recurring_select_dialog.js.coffee.erb
	app/assets/templates/recurring_select/dialog_template.html
	app/helpers/recurring_select_helper.rb
Merge branch 'master' into until_time_input

Conflicts:
	Gemfile
	Gemfile.lock
	app/assets/javascripts/recurring_select.js.coffee
	recurring_select.gemspec
getting demo app up and running
Merge branch 'master' into until_time_input
Merge branch 'master' into until_time_input

Conflicts:
	recurring_select.gemspec
Fix recurring select "until" feature.

Style fixes