SciDAVis - Improvements SVN-temp

- added doxygen short description to most classes
- applied qt3to4 to all source files in src
- merged in all dialogs from the "port_dialogs_to_qt4" branch that are fully ported
- ported all code lines to Qt4 that caused compiling errors (a lot)
Status of the QtiPlot Qt4 port:
- compiles without errors (using Qt3Support lib)
- it runs, but is very unstable and a lot of features don't work
- Qwt based functionality still disabled (commented out)