Control by keyboard, Sort content of lists and fixes some bugs in application layout

**Added Features:**
- Control by keyboard
 - Turn cards by pressing Ctrl(Strg) key.
 - Sliding to next/previous cards with arroy key right and left.
 - Mark card as known/not known in Learning mode with arroy keys up and down.
 - Rate card in Memo mode with keys 0-5.

- Sort content of list views by value
 - Cards can be sort by front or backside alphabetically (forwards/backwards) by clicking arrows in header row.
 - Card decks can be sort by name, description, category or created alphabetically (forwards/backwards) by clicking arrows in header row.

**Bugs fixed:**
 - Show correct tooltips for rating in Memo mode.
 - Show buttons in right size and with label in Learning mode.
 - Show Text, when box is empty in Learning mode and no more cards are available.

**Known Bugs:**
 - List headers are not shown in "My deck of cards", after sorting decks. (Appears only on Firefox. Works fine on Chrome).