Changed part of test/unit/ to use pytest framework.
Change to pytest

Conflicts:
	test/unit/jit/python/test.py
	test/unit/la/python/test_krylov_solver.py
	test/unit/la/python/test_linear_operator.py
	test/unit/la/python/test_matrix.py
	test/unit/la/python/test_scalar.py
	test/unit/la/python/test_solve.py
Replace tabs with space
Remove tabs, change to pytest
Change to pytest
Change to pytest
Clean up
Add cpp test, move output and convert to pytest
Bug fix
Make files executable, add #!/usr/bin/env py.test and remove __name__ == __main__
Remove tester.py
Add pytest for cpp. Should be reviewed.
Make cpp tests executable, add relative path and remove tester.py
Rewrite mechanism for setting backend in test_vector.py
Fix paths in test_time_series.
Setup fixtures properly for test_error_control.
Make test.py do nothing when imported...
Minor fix in pytest.ini.
Change from class to standalone fixtures in test_dofmap.py.
Add pytest.ini minversion = 2.4.