Update angular-bootstrap-select.js

Prevent the toggle directive from attaching itself to everything that defines a toggle attribute. This fixes an issue where bootstrap select would interfere with the built-in bootstrap dropdowns etc.
selectpicker now stays in sync with original select's ngModel
Merge pull request #6 from Shrugs/master

selectpicker now stays in sync with original select's ngModel
Thx @Shrugs
Merge pull request #5 from pauljmelia/master

Update angular-bootstrap-select.js
Updated README.md
removed grunt and bower to local dependencies
Added tests
build