the last step was moving the statics to a common class which is
initialized at startup.

Save some cycles by not using QTextBlock::text unnecessarily (since only
its length and the character at the block position were used).

This is to make it consistent with the rest of the settings ui.
When a checkbox is unchecked, the sub-check box becomes invalid, its
functionality is disabled, but it retains its checked state.

Merge-request: 1766
Reviewed-by: Thorbjørn Lindeijer <thorbjorn.lindeijer@nokia.com>

Merge-request: 1766
Reviewed-by: Thorbjørn Lindeijer <thorbjorn.lindeijer@nokia.com>

Merge-request: 1766
Reviewed-by: Thorbjørn Lindeijer <thorbjorn.lindeijer@nokia.com>

Merge-request: 1766
Reviewed-by: Thorbjørn Lindeijer <thorbjorn.lindeijer@nokia.com>

Based on the previous (referrable) line

Merge-request: 1766
Reviewed-by: Thorbjørn Lindeijer <thorbjorn.lindeijer@nokia.com>

Separating navigation history logic from updating of highlights.

Now the items are pasted to the parent of selected node. It is too
selected after the paste.

Reviewed-by: Kai Koehne