GitLab

    - deleting obsolete find modules
    - using HINT and adding default library and include path
      (CPP_INCLUDE_PATH and LIBRARY_PATH) in GSL, H5hut and HDF5 find modules

    - removing unused file
    - moved fieldlayout, mesh and layout to OpalData
    - started using smart pointers, removed lots of issues with destructors

Merge branch 'develop' into svn: new ParallelTTracker, refactored from the old. Now default is to have units. Still lot of places that need to be cleaned up and/or fixed.