Also introduce a indirection, modes have now types, edit and debug have
the same type, and editors do have a prefered type of modes instead of a
prefered mode.

That fixes the bug that if the prefered qml editing mode was set to
design, then in switching between qml editors would
- in Edit Mode: stay in edit mode
- in Debug Mode: switch to debug mode

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

Unfortunately, we still have a few ILocatorFilter based classes that
don't play nice with threads.

Reviewed-by: Friedemann Kleint

Discovered with change b7fd293098 in Qt master

Using more *::Constants::ICON_* where it makes sense and
wrapping the file names into QLatin1String where they were
missing.

The increased usage of the ICON constants needed a few more
cross plugin includes of *constants.h, here and there.
I think that it is OK, since the dependencies were alredy there
icon resource wise.

Also unify some method naming.
Use the new feature to add clear buttons to the Locator,
and the find tool bar.

Task-number: QTCREATORBUG-705

A mostly mechanical change.

Reviewed-By: con

Especially for the file system filter, it's better not to block while
collecting all the file names by first iterating over the file system.
Now, the filters return an iterator, and the search thread takes a file
from it, searches it, and takes the next file.

This also unifies the file iterator for the custom locator filters and
the find in files on file system search filter.

Task-number: QTCREATORBUG-1690

Reviewed-by: ossi

Reviewed-by: Jens Bache-Wiig

- fixed some RTL issues. I removed isSideStored
and useLayoutDirection. Instead we simply flip the
sides if RTL is in use.
- added the fader animation and clear icon that we
use in Designer already.
- fixed the double toplevel popup focus issues we
had with the locator menu.
- removed some redundant labels and reset buttons

Some categories do not have icons yet, unfortunately.

Do some focus handling hacks on windows (only)

Reviewed-by: jbache

Reviewed-By: con

Go to About Plugins and enable/disable plugins from there.

Reviewed-by: mae