Minor refactoring

I like your idea and project on multi-select very much ! So I read your code carefully and find some places can be improved:

1. give "var" keyword for the local variables to prevent them from accessing globally.
2. decrease the loop time when assembling the button label

And some questions:
1. when filtering on the data, the image tag will be considered as well. This means when some user input "img", all the available options are returned. I think this is not very reasonable.
2. findUpTag method is not used anywhere in the code (including the template).
3. whether the last part of $timeout in updateFilter method can be removed ? Since I cannot figure out why it is used. Would you kindly tell me the reason for it ?

Thanks very much !