Making dbus optional in Calligra

[Sebastian Sauer]

What I would like to do is to introduce in Calligra a way to completely 
disable any use of dbus. The target would be to 1) make Calligra compile 
with #define QT_NO_DBUS and 2) make Calligra optionally compile without 
support for dbus even if Qt-dbus is available.

The idea is to address one of the issues named by Mek in his amazing 
blog-post about the port of Calligra to Android ( see 
http://blogs.kde.org/node/4521 ). The issue is that Android does not 
ship with dbus.

The idea would be;
1. introduce a new cmake flag that allows to disable dbus Caligra wide. 
Per default dbus is enabled except Qt was compiled without support for it.
2. introduce #ifdef's all over Calligra to proper disable / not compile 
any code that makes use of dbus when dbus was disabled.

Good idea? What do you think?