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
Merge pull request #89 from caponica/new_date_formats

New date formats