Removed unnecessary addCurrentFieldToHistory method from Controller and re-added getFiles overrides in media fields.
Started work on a <Drawing> field, basic UI implemented but much functionality missing.
Ensure that gallery is refreshed when a new capture is made by setting mediaItemsChanged before entering onCapture()
Lots more work on Drawing field and corresponding UI, plus support for custom/default attributes in parser.

Needs testing!

Signed-off-by: benelliott <bengelliott@gmail.com>
More tweaks to Drawing UI. Issues that remain:
- capture button vs. capture more button - current implementation is a bit messy
- erasing/resetting without having to confirm first?
Created a "canvasColor" variable to avoid shadowing the regular field backgroundColor.

Signed-off-by: benelliott <bengelliott@gmail.com>