MiniPauker Code

- scroll down now stops when reaching the bottom
- scroll up/down added also to the Repeat*UI
- small fixes of new features

1. Added experimental Page Up/down scrolling for learning screen (keys 2, 8)
2. Commands for the Learning UI as buttons
3. Learn/repeat buttons now on 1 row

adding a forgotten class...

- When repeating:
-- show how many card there are yet to repeat
-- when done, show when another card is going to expire (expiration less than 1 hour ignored) (#2065063)
- Repetition: Added Edit and Delete buttons (#3012517)
- Learning: Added Delete and Stop commands (#1928138)
- Support opening Pauker files with the extension .xml.gz (#2859558)
- Export file now contains the current time stamp in the readable format yymmdd-hhmmss

little cleanup

Fixed broken storing of the current session name.

- Major refactoring:Im.ExportController, LearningC. extracted out of the UIController
- UIComponents now calls updateView on itself before displayed (or before displaying an alert that will be replaced by the UI) => no more need to tell it it needs to update itself, plus only the visible component updates itself =>
--Fixed #2349680 - Answer is shortly shown when "remembering"

Major refactoring (yet to be thoroughly tested):
- ImportExportController and LearningController extracted out of UIController
- Introduced PaukerDisplay for centralizing view management
- In tasks, switched from prev/next Displayables to the use of ViewNavigation
- UIComponent now calls updateView itself before being displayed
- Repeat Expired/Unlearned highlighted when they are non-empty (works only partially, namely the highlighting disappears e.g. when the item is hovered over)
- Open / Import UI: refactoring for better readibility incl. replacement of item indexes with their labels in action handling

- Refactoring: PaukerPrefs and CardBatches factored out from PaukerCore
- Swapped Cancel and Save&Quit buttons in the save dialog to correspond to the normal meaning of the keys
- Added the option to automatically load the previous session upon startup

1. Fixed bug 2995756 (cards can't go to batch 8 - a missing break in a switch)
2. PaukerPrefs factored out from PaukerCore.