added ability to remove data from a disk store by key

Ignore-this: bf7267f0b8e09e2a4dd2bf2650e6131c

darcs-hash:20140203234024-c21fe-d15827d24f5aabeeab36f1c938c960fd02ffd57e
updated app editor to be able to add data to an app and remove data

Ignore-this: 9b3b4aeb6e12d22a12b5ed3ea064b1cc

Added a new data tab in the app editor which allows you to add and remove data by key.
You can add files too! However, the interface is pretty simple at the moment and needs
to be more error proof.

darcs-hash:20140203234127-c21fe-654cc3888f1d77eefc603b091cc8fbcd94567452
app editor now sends the data with the code

Ignore-this: 78b7e348aad0c3b188930a98075376f

When the data is updated through the UI, the data is sent with the code to the peers.

darcs-hash:20140204032905-c21fe-7fc0d5fb0ec716dfccd8797c7ebc1b48e2596e02
added remove to the disk store lua api

Ignore-this: 3c38eed0044643bff25db37939f420ec

darcs-hash:20140204033012-c21fe-8b4855296b198dc0b437cc9f8d060593ce4ce082