fix(datepicker): mark input field as invalid if the date is invalid

Closes #1845
fix(datepicker): rename `dateFormat` to `datepickerPopup` in datepickerPopupConfig

Closes #1810
fix(dropdown): unbind toggle element event on scope destroy

Also, change the way disabled dropdownToggle is read from `attrs` instead of element property.

Closes #1867
Closes #1870
demo(datepicker): add type attribute to buttons

Closes #1890
Closes #1894
chore(ci): switch off IE testing on TravisCI
fix(typeahead): loading callback updates after blur

Fixes #1822
Closes #1904
test(pagination): clean some injections

Closes #1895
feat(dropdown): focus toggle element when opening or closing with Esc`

 * Improve accessibility.

Closes #1908.
fix(timepicker): evaluate correctly the `readonly-input` attribute

Closes #1911
fix(karma): exclude demo files

Closes #1889
fix(typeahead): incompatibility with ng-focus

Used timeout to avoid $rootScope:inprog error

Fixes #1773
Closes #1793
chore(typeahead): fix typo in comment

Closes #1925
fix(carousel): correct glyphicon

Fixes #2006
Closes #2014
chore(dropdown): remove unused var
Closes #2023
feat(button): allow uncheckable radio button

Acts as a hybrid checkbox/radio-button, selecting exclusively among the button set, but also allowing the selected item to be unselected, leaving the button set without a selected item.

Closes #1760
feat(typeahead): add `aria-owns` & `aria-activedescendant` roles
fix(dropdown): do not call `on-toggle` initially

Closes #2021
fix(modal): give a reason of rejection when escape key pressed

Fixes #1956
Closes #1991
docs(typeahead): add `typeahead-on-select` callback parameters

Closes #2047
feat(datepicker): make widget accessible

 * keyboard navigation
 * WAI-ARIA roles
 * popup will close on escape on input or calendar
 * handle focus when closing popup

Closes #1922

BREAKING CHANGES: popup calendar does not open on input focus