Add ability to make some OPTION tags selected by default as per provided data

Just set the 'selected' property to true on the data item
Works also for optgroup's options.

Also use jQuery tag constructor and attribute setter to avoid HTML filtering issues
Add ability to handle the "caption" property from the dataprovider() to display a title on hover of each option label

Update doc
Create the `title` attributes from data
Show that the dataprovider method supports `selected` and `caption` properties
Document support of `title` attribute on OPTION tags
Ignore intelliJ project file
Set the input tag type and name with jQuery's attr() method to avoid any string escaping issue

Factorise some code too
Merge pull request #401 from kayhadrin/features/support-preselection-and-caption-on-options

#385, #384: titles for options, supporting dataprovider; dataprovider with preselected options.