New feature using Mongo

Using the Mongo version of our database application, add a feature that uses a capability of Mongo/PyMongo.

An example:

1. Using a batch file or some patience, add a few dozen more tasks.
2. Add a search feature that allows submitting a search string. (Much like the "new item" feature allows submitting a string)
3. Use the string to search for tasks containing a string and display only those tasks on the task list page.
4. It would be nice to have some way to clear the search selector.