Workflow Tracking updates

- Replaced the HTML5 date and time input types with JQuery datepicker and timeentry plugins
- Modified the session table save logic to accurately reflect the user changes to a given workflow
- The start, end event numbers now correctly updated for the second tab
- Added error handling to deal with possible null DateTime values obtained from the DB
- Last modified workflow values now retained in the session
Merge branch 'master' of github.com:MarkVSullivan/SobekCM-Web-Application