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.