Delete Doxygen blocks duplicated in both .h and .cpp files.
Fix incorrect argument names in \param blocks. Fix filenames
in \file blocks. Fix broken Doxygen syntax (broken numerated
lists containing more than 9 items, invalid HTML tags, broken
links in \ref and malformed math equations). Wrap code blocks
inside \code ... \endcode.

[BufferSystem] moved clearing of recv buffers from endCommunication to
startCommunication

- templated buffer classes allow the buffer systems to work with custom
  buffers, e.g. buffers of GPU memory

- Bug occurred if a BufferSystem (or communication scheme) was copied
  and the first object went out of scope.
- Internally a pointer was kept which was still pointing to the original
  BufferSystem

Fixes #16

If you have access to the old closed source waLBerla repository, you may restore the complete history with the following command
git fetch git@i10git.cs.fau.de:software/walberla.git 'refs/replace/*:refs/replace/*'