Added allowClear & DataList Excludes

Added allowClear option to Select2 init to allow native clearing of select2 element once an option has been selected.

Added DataList Excludes array to allow for extended control over the returned list.

Signed-off-by: Zann St Pierre <mail@zann.com.au>
Merge pull request #2 from zannstpierre/master

Added allowClear & DataList Excludes