Task-number: QTCREATORBUG-2300

This should make the indenter less strict and annoying for non-standard
indentation styles.

Reviewed-by: Roberto Raggi

Thanks to this patch we can move the filtering of C++ symbols
in a background thread.

Done-with: Erik Verbruggen

The function always switched to Edit Mode, which was the cause for
several bugs. Since openEditor() already does switch to the right mode,
the function is not really needed.

The following actions now respect the prefered mode of the editor:
"f file"-locator
The Open Documents list
Editor history navigation

Task-Nr: QTCREATORBUG-2243

Task-number: QTCREATORBUG-2111

This makes sure styles are consistent for the editor and the quick fix
engine.

... for doxygen. Change logic for known empty keywords to be replaced
by an empty string.

Task-number: QTCREATORBUG-1854

Done with: Thorbjørn Lindeijer

Task-number: QTCREATORBUG-1919

Required refactoring of the search result window to show real trees of
search results.

The backend is the backend from the Locator filter, which is a bit
outdated now.

Reviewed-by: Roberto Raggi

Don't complete the current item when pressing special characters (e.g. `;') if the completion is automatically triggered.

Done-with: Erik Verbruggen