Currently the build without implicitly included precompiled header
is not supported anyway (because Qt MOC source files do not include
stdafx.h, they include plain headers).
So when we decide to support building without implicitly included
precompiled headers we'll have to fix all the headers anyway.
If we start logging in and we know, that some of the authorization
keys were read from the hard drive, not generated, we destroy all
the existing authorization keys and start generating new keys.
John Preston