Fixing bug related to choice destroy click.

This particular issue was tricky to debug, but essentially there was
an issue with clicking to destroy a choice in the multi select.

The current bug can be reproduced by following the steps here:
https://github.com/harvesthq/chosen/issues/346

I tried to solve it by forcing the field to blur after the choice
delete link was clicked.  However, there was a race condition
involving @pending_destroy_click, container's mouseup event, and the
destroy link's click event.
Just a simple hack for adding page up & page down support, Cheers ^_^.
Merge commit '6f71f04b47947244c6e0e9a15ed4907e48715782' (page up/down support)

Conflicts:
	coffee/chosen.jquery.coffee
Merge branch 'destroyClickFix' of git://github.com/digidanny/chosen
Rebuild
Rename 'data-placeholder' to 'data_placeholder' to fix Jinja template compatibility