test(md-slider): Coverage for ARIA attributes
update(docs): Tabs in source view should not be tab order when not visible

Updated open/close animations and styles of source view.
Now skips Tabs pagination updates when tabs are not displayed.

Fixes #501
feat(mdThemingProvider): add alwaysWatchTheme options, fix docs
feat(radioGroup): add up/down arrow navigation

Closes #538
chore(travis): dont build pull requests
fix(sidenav): clean registry when element is destroyed

Element registry is currently kept even after element
is removed from DOM. Appart from the memory leak, it
also disable future components with same handle from
beeing pulled from the registry, for example when users
navigate away/back to a page, DOM is reloaded but new
component does not work anymore (old registry
component is called instead of the new one)

@ajoslin reported in referenced issue that registry
component will be refactored. Until then, this patch
should fix the bug on the component side.

Closes #473,#474
fix(md-button): improve a11y: make title, aria-label work

Closes #512
update(docs): code highlight block positioning corrected
chore(travis): make sure it doesn't build on pull requests
chore(): add default-theme to gitignore
refactor(button): replace with an anchor or button

Closes #423. Closes #508. Closes #230. Closes #558.

BREAKING CHANGE: When using the `<md-button>` directive, the compiled
element will now be a normal `<a> or `<button>` element with the class
`md-button` on it. There will no longer be `<md-button>` elements in
your final DOM.

This means that any css referencing the `md-button` element selector
should now reference the `.md-button` class selector.

Change your code from this:

```css
md-button {
  color: red;
}
```

To this:

```css
.md-button {
  color: red;
}
```
refactor(aria): add expectWithText, expectAsync methods

jQuery is also no longer a testing dependency.
style(docs): fix toolbar icon alignment on api docs
Added new directive `mdTextarea`
- Extracted the link function of the `mdInputDirective` to reuse it for the `mdTextareaDirective`
-`mdTextarea` is configurable with `rows` and `cols`, but behaves the same as `mdInput`
Added `textarea` support for `mdTextFloat`
```
<md-text-float rows="4" cols="50"
                            type="textarea"
                            label="{{labels.intro}}"
                            ng-model="user.intro">
 ```