fix(copy): Vendor CSS was ignored during copy

Closes #305, #275.
Replace ngmin with ng-annotate

ng-annotate is faster and more robust. Furthermore, @btford is okay
with deprecating ngmin and annointing ng-annotate as it's successor.
See btford/ngmin#93, specifically
https://github.com/btford/ngmin/issues/93#issuecomment-43699038