Added support for align-items: stretch in grid

Now you can do:

```
<div class="row row-stretch">
    <div class="col">Very<br />Much<br />Text<br /></div>
    <div class="col">Short</div>
    <div class="col">Shrt</div>
</div>
```

All columns will have equal heights. Especially useful when 'simulating' tables with the grid system.
scss(popup): max-width 100% for huge content areas

Closes #1031
fix(tap): Prevent clicks from firing after scrolling, #579
feat(grid): Added .row-baseline and .row-stretch
Merge pull request #1050 from driftyco/pr/1049

feat(grid): Added .row-baseline and .row-stretch
fix(checkbox): stretch checkbox's clickable area to full width
Merge pull request #1053 from driftyco/pr/1049

fix(checkbox): stretch checkbox's clickable area to full width
Add travis integration for Slack
.item-select cursor: pointer
bower: change version to ^1.2.12
docs(platform): Explain ionic.Platform.ready() further
run not ran
fix(tap): Remove 300ms delay when tapping select elements
test(tap): add some more tests for taps
scss(back-button): make position:absolute while fading out

Fixes #1069
feat($ionicModal): pass modal instance to modal.shown/modal.hidden events

Fixes #1065
fix(tap): Do not preventDefault after input focus, #1068
test(click): fix html test
test(tap): split apart ignoreSimulateClick tests
test(tap): Tests for ignoreTapInspect, recordCoordinates, isRecentTap