Fix up unit tests. Check config url with isURL.

No issue
-validate url in config.js using validator.isURL
-fix up async flow in bootstrap unit tests
-make sure done handler is called on async tests
updated express-hbs to 0.7.10
Updated grunt-update-submodules to 0.4.0

closes #2503
 - It can now have custom additional parameters to `git submodule update` instead of always having `--init --recursive --merge`
Infinite Scroll on Posts List

closes #2414
- Add PostsController with loadNextPage action
- Collect and store pagination info from PostsRoute into PostsController
- Use `store.filter` on PostsRoute model hook to auto-update posts list template as post models are added to the store
- Add content list view and use it to check for scroll event
- Make PostRoute only load a post that's already in the store, until we figure how to load multiple pages on refresh
- Add util function from clientold that concats error messages from server response
Merge pull request #2838 from aiampogi/master

Updated grunt-update-submodules to 0.4.0
Merge pull request #2837 from iBotPeaches/updated_express

updated express-hbs to 0.7.10
Merge pull request #2834 from appleYaks/infinite-scroll

Infinite Scroll on Posts List
Merge pull request #2835 from jaswilli/fix-tests

Fix up unit tests. Check config url with isURL.
escapes meta title/description

closes #2663
adds unit-test
Merge pull request #2686 from iBotPeaches/unsafe_meta

escapes " in meta title/description
Ember: correct editor layout and other niggles

no issue
- Fixes the editor view so that the layout is correct
- Remove default title
- Fixes a couple of scoping issues with notifications
Added popover component

Closes #2418, #2714
Ref #2446, #2565

- Added and injected `popover` service to globally control popovers
- Added `gh-popover-button` component
- Added `popover-mixin` for popover and popover-buttons to mixin
- Added body-event-listener mixin for popover service to watch for body
  clicks with
- Post settings and post save button both now use `gh-popover`
- Added hacks to `ember-hacks.css` to make popovers work until ghost-ui
  consolidates functionality
Export backup prior to migration

Closes #847
- Added logic to export database to the `core\server\data\` folder prior
to beginning a migration.
- Factored out versioning logic from migration to prevent circular
references
Merge pull request #2840 from novaugust/popover-service

Added popover component
render html in notifications

fixes #2844
Added error link on 404 pages

closes #2298
- added hyperlink to error templates
- added class for styling hyperlinks on error pages
Merge pull request #2792 from jomahoney/2298-error-page

Added error link on 404 pages
Merge pull request #2854 from iBotPeaches/render_notifications

render html in notifications
Ember cleanup: double quotes + removed bad tag

- All HTML / Handlebars should use double quotes
- Removed a tag I meant to remove earlier
Ember cleanup: single quotes for JS

- All JS should use single quotes