* When displaying an error, scroll to the top of the page.
* Rename a few of the filter titles to better match the titles of the table on the process instances list page.
* Add error_message to the task object - so if a task is in an error state and has a message, we send it to the front end.
* Handle errors on the Interstitial page - so if an error happens during execution it is diplayed, and if an error happened previously, we show it.
* Return the last Errored Tasks if no READY or WAITING tasks exists when calling the Interstitial endpoint.
* Cleaning up icons so they are a little smaller and more consistent.
* Always show that action column.
* Improve the state managment and layout of the interstitial page.
Dan