fix(tooltip): update tooltip content when empty

Closes #1348
fix(datepicker): set default zero time after no date selected

Closes #1065
fix(datepicker): fire `ngChange` on today/clear button press

Closes #1379
fix(tooltip): support IE8
fix(tooltip): unbind element events on scope destroy

Closes #1339
Closes #1346
Closes #1400
refactor(alert): move logic to controller & add tests

 * Add missing tests that `close` button is actually visible
   Tests were passing even if link function was empty.
fix(datepicker): remove datepicker's popup on scope destroy
fix(datepicker): remove edge case position updates

Closes #1296
feat(typeahead): add typeahead-append-to-body option
refactor(buttons): remove some code duplication
fix(modal): Grab reference to body when it is needed in lieu of when the factory is created
revert(typeahead): prevent accidental form submission on ENTER

Closes #1298
This reverts commit 253c49ff26c1bb6c324a0549bc51ee4f45f66429.
fix(modal): focus freshly opened modal

Closes #1187
feat(modal): add modal-open class to body on modal open

Closes #1254
docs(typeahead): add async version of the demo
docs(typeahead): show custom template implementation

Closes #1441
fix(modal): properly animate backdrops on each modal opening

Closes #1267
test(tabs): get test coverage to 100%

- Add one removal of a non-last tab to test one last branch
- This excludes the deprecation message for the tabs directive.
refactor(tabs): remove unused tabs directive
chore(tabs): Add tests for nested tabs

Relates to #783