Added basic search

Basic search functionality we worked on Saturday w/ a few additions.

- Force the view to redraw on keyup/filter, this prevents a row which happens to end up in the same position after filtering from remaining indented
- Remove expand/collapse if depth is 0, alternatively might want a flag to indicate sorted/flat view.
- Added check for args.grid as this was failing a qunit test.

*Note: Tree.prototype.sort will need to be reviewed as sorting has flattened the folder/file list and the results appear out of order due to hierarchy.*