Merge pull request #106 from mwarusz/master

wip on new grid
adding an assert in open_1d + some comments
missing include + indentation changes in bcond.hpp
adding output svg file for paper_example_2
updated plot.py for err_isolines test; svg plots into repo
updated txt tilfe with output from test err_isolines
updating tests to the new domain geometry interpretation (+some better error reporting in tests)
fixing hook_ante_loop in mpdata_rhs_vip_common
adding a missing include in arakawa_c.hpp
cleaning up vctr_alng exchanges
fixing dfl option for G=1
fixing an assert in donorcell iga
changing bc to open in test_rotating_sphere
re-enabling all test variants in rotating cone test
switching to open bc in paper example 1
removing calls to bcinit and shrinking halo in vctr_alng calls
adding new versions of pi() for integer and mixed-int-rng_t arguments
a small rewrite of boundary conditions (open bc is now based on zero-div condition for vectors and zero-grad condition for scalars; no more bcinit)
parameterising opts in spreading_drop_1d