Copy token data on token creation

It's not a deep copy (which may be needed in some cases), but this should
prevent cases where the token data is being modified (like in the :createtoken
event) from contaminating the data source (like autocomplete or typeahead).
Fix some typos in some comments
Use jQuery.data to store token attributes

This should also resolve #102, as arbitrary data can now be set on the attributes and it is carried throughout the token's lifetime.
Merge branch 'copy-values' of github.com:paxswill/bootstrap-tokenfield into paxswill-copy-values

Conflicts:
	js/bootstrap-tokenfield.js
Merge branch 'paxswill-copy-values'