Add the ability to search pattern and search rule to serialize
themselves into a QByteArray and store that along with the
remaining meta information about a search in a custom attribute
with the Akonadi collection representing the search folder.
Don't leak the pattern in teh searchwindow, keep it by value.
Add some comments to clarify what happens. Harmonize quick
search to real search and search folder re-opening so they make
sense. Port KMSearchRule to shared_ptr. Finish some tods left
from the initial port.
svn path=/trunk/KDE/kdepim/kmail/; revision=1111085