Minor fix in state keyCaptures

Mixing up next and previous.
Refactor keycapturing in sidepanel
Refactor key capturing once more.
Extract a sidepanel service
Use a watch on fold status in sidepanelFolder
Add default keybinding to toggle sidepanel
Refactor sidepanel keyCaptures once more
Refactor sidepanel service
Minor refactor in sidepanelFolder directive
Merge pull request #201 from latin-language-toolkit/sidepanel_updates

Sidepanel updates