- remove deprecated features
- update ABI and API versioning

- updated INSTALL
- change the ELPA vesioning number
- update Changelog and RELEASE_NOTES

Still to do:
- ABI versioning
- API version number
- Release notes
- Changelog
- Issues
- remove deprecated features
- update of API documentation

also introducing --with-likwid parameter to the configure script

Can be used to compile with likwid and to enable the likwid to measure
performance of individual compute steps

with AC_COMPILE_IFELSE in the configure.ac script

Add parts to configure.ac and Makefile.am. There is now an additional
flag --enable-python-tests. The tests require the pytest package.

The implementation of the test is a bit hacky because it takes
wrapper.so from .libs. This should probably improbed for better
portability.

By default, python wrapper is not built, only if this switch is
specified.

- depends on python, cython, mpi4py and numpy
- currently only dependency check on python
- should be done optionally
- converts wrapper.pyx to wrapper.c using cython, then compiles this to
  a python extension
- installs the files such that they can be imported with `import pyelpa`
  in python