Add custom class parameter

[cedricdelpoux]

This PR add the possibility to add a custom class parameter to the pickadate directive.
Users could customize the calendar.

Exemple :

<div pickadate custom-class="myCustomClass"></div>

Result :

<div class="pickadate myCustomClass" ...>...</div>

[gschammah]

hi @cedricdelpoux

Thanks for your PR. There are 2 ways of accomplishing what you need without the custom-class parameter.

1. Wrap the datepicker in a div with your custom classname
2. Check the branch Feature/templates #47. Is not finished yet, but it will allow you to create a custom template (probably what you need)

I prefer to add the ability of creating custom templates than adding custom classes.

Thanks a lot!