Find recently errored process instances

[burnettk]

new feature request: be able to view a list of process instances by date errored. i guess errors are currently stored in two database tables: process instance event and task event. it would also be useful to be able to see the error in the same interface, but seeing the ones that have errored most recently is the first priority. note that process models can be configured to go into the "suspended" status instead of "error."