Added some British formats to the class

The formats added are needed for a current project. I have also reformatted the comments so the example is first and the description comes at the end after a comma.

Two other queries about this process... is there any appetite to create a more robust mapper between ICU and Moment?
http://userguide.icu-project.org/formatparse/datetime#TOC-Date-Time-Format-Syntax
http://momentjs.com/docs/#/displaying/format/

And if the class name in date.xml could be parameterised then it would be possible (easier) to use a local variant of MomentFormatConverter instead of editing the bundle. Then again, perhaps this way encourages more community action ;)
Added link to Moment formats

To make it as easy as possible for other people to find the format syntax and build new mappings
Added tests for new date formats
Added datepicker_use_button option

Note that the new option does not use the dp_ prefix since it's not a datepicker javascript option. It is used in the Twig template to control the HTML, which then controls whether a button is used for the datepicker or not.
Added test for presence of datepicker_use_button
Implemented datepicker_use_button option

If datepicker_use_button is false then the extra HTML elements for the activation button are not rendered, and the datepicker is activated by clicking on the input field instead.
Merge pull request #89 from caponica/new_date_formats

New date formats
Updated to work when datepicker_use_button is not set
Use the attr parameter to pass format options through to date widget when not using a separate button to activate the datepicker widget
Merge pull request #91 from interstroom/master

Add Symfony v2.5 to travis
Added documentation for dp_* options and new datepicker_use_button DatePicker options
Fixed typo in doc
Merge pull request #90 from caponica/datepicker_optional_button

Added option to use datepicker without a separate button / icon
Added pre_bind_data_closure option to sonata_type_collection
Merge pull request #94 from Bladrak/collection_type_pre_bind_closure

Added pre_bind_data_closure option to sonata_type_collection
Renamed pre_bind_data_closure to pre_bind_data_callback
Merge pull request #95 from Bladrak/closure_callback

Renamed pre_bind_data_closure to pre_bind_data_callback
Added php 5.6 to .travis.yml
Merge pull request #96 from pulzarraider/patch-1

Added php 5.6 to .travis.yml
Update SonataCoreBundle.sk.xliff