Change default kits on Mac OS X to use LLDB instead of GDB which is not supported anymore in Mac OS X

Apparently, the support for the GDB provided by Apple has been dropped in 3.1.

http://blog.qt.digia.com/blog/2014/03/04/qt-creator-3-1-beta-released/

Still, the default kits on Mac OS X use it. All kits shall be changed to lldb. Otherwise, debugging on Mac OS X is not possible without a help from a search engine......

Might be related to QTCREATORBUG-11887

======== This is how the problem first appears to a user ===========

I went back to the Qt (5.3.1 form the SDK) on Mac to test a desktop app and had to realize that the debugger (gdb by default in the kit for OS X clang 64) does not start telling that python is an unknown command.

I just discovered this discussion on 100% the same matter:

http://qt-project.org/forums/viewthread/45760

and retested the suggested workaround. lldb works as mentioned in my case as well. Just to be sure, I cleaned my env and removed Mac ports and other instances of python from the PATH, but the problem remained.

This is my env:

16:45:05: ~/projects/AntiDouble:> echo $PATH
/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/opt/X11/bin:/Users/Shared/BDT:/usr/local/munki
16:45:12: ~/projects/AntiDouble:> which python
/usr/bin/python
16:45:30: ~/projects/AntiDouble:> which gdb
/usr/bin/gdb
16:52:10: ~/projects/AntiDouble:> gdb -v
GNU gdb 6.3.50-20050815 (Apple version gdb-1824) (Wed Feb  6 22:51:23 UTC 2013)
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "x86_64-apple-darwin".
16:52:18: ~/projects/AntiDouble:>