Some D-Bus work in KMail:

- Remove the existing org.kde.kmail.kmail/kmailpart/mailcomposer.xml files, and let them be generated at build time instead. This is done by extracting the slots and signals marked with Q_SCRIPTABLE.
I had to adjust the CMake files of all users of the XML files to use the one from the build directory now.

Currently, the XML files are also installed. I am not sure if this is a good idea, as that implies we have to keep some sort of compatibility.

- Fix incorrect D-Bus path and method call in the summary view. Now the generated interface is used instead. Checking the accounts with the sync actions works again now.

- Some DCOP->D-Bus renamings in comments

- Some style fixes around D-Bus related lines

The D-Bus test of KMail and the Kontact KMail summary still work.
This needs the new FindQt4.cmake from kdelibs.
This probably needs a clean build.

I did not touch the groupware interface or the SMIME security config page (which talks to Kleopatra). This is left for KDAB to fix, but it would be nice to contact me before.