made the <editable-group> work inside of an ng-repeat.

The code in this commit isn't in a "working state" but the "hard bits" are
solid.
reenabled the remove buttons
removed some obselete code from client controllers
id filter now fails silently
include the add button on an <editable-group> if $last == true

Don't think this works yet
changed the grunt server to run on 0.0.0.0 which works with port forwarding
moved the shared logic of the {person,project} services into services/models.js
fixed the add button by changing how the models are stored