feat(bootstrap): Add bootstrap-compatible stylesheet

Add support for Bootstrap colors and transitions..
Merge PR #155
feat(tagsInput): Add support for some Bootstrap classes

Add support for the following Bootstrap classes:
- input-group
- input-group-lg
- input-group-sm
- input-lg (via ti-input-lg class)
- input-sm (via ti-input-sm class)
- has-feedback
- has-success
- has-error
- has-warning

Closes #78.
feat(configuration): Add setTextAutosizeThreshold method

Add a new method to the tagsInputConfig service to allow the threshold
used by the tagsInput directive to re-size the input element based on its
content to be configured.

Closes #181
chore(grunt): Add Boostrap files to the compress task
chore(README): Update Installing section [skip ci]
chore(grunt): Fix update-bower-version task
chore(packages.json): Add bugs and keywords properties
chore(grunt): Generate tarball for NPM
chore(release): Release v2.1.0
fix(tagsInput): Fix has-success, has-warning and has-error classes

Fix Bootstrap validation classes by removing their dependency on the
has-feedback class.
chore(grunt): Add build folder to NPM tarball
chore(release): Bump version to 2.1.1
chore(release): Release v2.1.1
chore(README): Fix header styling
docs(tagsInput): Fix type option documentation [skip ci]
docs(README): Fix link to the API documentation page
chore(package.json): Add main property
feat(tagsInput): Enable ngFocus and ngBlur native directives

This adjustment makes sure the outer (directive) element is focussed when the input field receives focus, and blurred when the input field loses focus. That way, Angular's native ng-focus and ng-blur can be used on the directive element.
remove ng-blur and ng-focus test page code