Remove "Snapshot" module and integrate its functionality into the stack
Current snapshot workflow:
- Change from current stack level to another
- Click on [take snapshot]
- Go back to current stack level
- Click on last snapshot to activate comparison slider
-> get back to work and compare images
- Click on any but current stack level to activate comparison slider between current and selected stack level.
-> get to work and compare images
The user doesn't really need to (or want to, proably) deal with taking snapshots, the user only needs them to be there whenever he/she wants to compare stack levels.
This should™ be possible by creating an anonymous snapshot at the current zoom level whenever the user clicks on a stack level and then switching to compare mode.
Leaving compare mode could then be possible by pressing [Esc], clicking on the current stack level or via an [exit compare mode] button somewhere by the stack or near the image.