Directory structure

The new mca2 directory structure is as follows:

 - mca2
   - script                         (bash and python mca-scripts)
   - etc                            (file templates and common config files)
   - libraries                      (mca2 sources)
     - kernel                       (mca kernel sources)
     - math                         (some additional math functions used by several user libs)
     - qt                           (some basic qt classes and functions used by mcagui and mcabrowser or other plugins)
     - general                      (some basic mca modules)
     - fileio                       (some mca modules for file IO)
     - audio                        (some mca modules for audio processing)
     ... any other user library
   - tools                          (mca2 tools sources)
     - gui                          (mcagui sources)
     - browser                      (mcabrowser sources)
   - build                          (temporary files, created by scons, is empty until a build process was started)
   - export                         (target directory, empty until a build process was started)
     - i686_Linux_debug             (target dependent sub directory)
       - bin                        (built binaries)
       - lib                        (built libraries and plugins)
       - include                    (for installation needed include files)
     ... any other target platform