Scalebar for images and plots

See release notes for this release on GitHub: https://github.com/ehennestad/scalebar-matlab/releases/tag/v1.2.0

- Added options for including semi-transparent background
- Fixed behavior when XDir and YDir of Axes object changes

Update image

Fix potential infinite recursive callback loop

Changed file

Adds to current axes if parent is not specified
Fixed bugs when updating position in axes where hold is 'off'
Updated doc

Updated image