First take at wallpost creation.

It works when you're logged in but there's still lots of details to work out.
Add error support in ember

- Check for errors when posting records
- Split WallPostForm into Media- and Text-
wip
Work on delete wp. Set default for video_url.
Confirm wp delete. Refresh form after post.
Some minor changes and comments
Simplified project binding on wallpost
Changes after review B&L
Merge pull request #156 from onepercentclub/wallpost-ember-post

Wallpost ember post