caUtils now print the error count if there's more than one
Get ca_data_exporters ready for basic UI implementation

- added change logging
- added utility to list all eporters
- loadExporterFromFile doesn't just dump/print errors but adds them to
call-by-reference parameter
Export UI changes

- allows exporting on record level via editor inspector (sidebar
widget) if permissions allow and there is a suitable mapping
- allows uploading mapping spreadsheets via UI
- batch export is still broken, will be next

Also, the navigation location is a bit questionable at the moment but I
couldn't come up with a more suitable place. Will probably move soon.
Added progress callback function to export from search expression. Also added utilities to find out file extensions and content types for export downloads, depending on the format.
Single record export now uses new utilities
Added batch exporter with shiny progress bar and file download. Still under the wrong menu.
Moved exporter UI to manage. Still not quite there but better than before.
Export access control improvements
Added semi-decent navigation between exporter screens via very basic inspectors.
Better error handling in batch exporter UI
Improved error handling for item-level exports and improved batch exporter navigation
Merge branch 'master' of github.com:collectiveaccess/providence