Added auto-prefill from hidden field if a hiddenTagListId option is defined. Also consolidated removed duplicate code into a new 'prefill' function.
Prevent double-initialization of TagManager
Correct spelling delimeter -> delimiter.

(old spelling still works but is deprecated)
Update Typescript
Add new API parameter: 'typeaheadOptions'. This allows you to pass-through parameters to the bootstrap typeahead.
Reduce complexity of event detection.
- Removes global variables isValid and queuedTag
- pushTag() function now just has one parameter, i.e. "the tag to push"
- Typeahead detection refactored into methods
- Add some utility methods to reduce duplicate code