[Feature] Autocomplete for dependencies

Fixes #21.

- Using ng-tags-input for dependent tasks.
- Added bower resolution for AngularJS, bumped up AngularJS and dependencies versions.
- TaskListService.getFilteredTasks and unit tests.
- Removed unneeded dependency building logic. Now everything is against `dependsOn` property, no more `dependsOnText`.
- Fixed dependency on own task. Fixed dependencies not being shown.
- Removed example data.
- Adjusted position of tasks in graph.
- Adjusted styles for tags.