don't pass the eclipsewriter to the simulator anymore

i.e., the simulator does not deal with any output operations
anymore. This makes sense because report steps are handled by
Opm::TimeMap and the constructor for the simulator already needs more
arguments than appropriate even without this...
Merge pull request #106 from andlaus/sim_fibo_ad_remove_outputwriter_from_simulator

don't pass the eclipsewriter to the simulator anymore
Removed calls to WellsManager() constructor which uses old EclipseGridParser.
Merge pull request #109 from joakim-hove/remove-old-WellsManager

Removed calls to deprecated WellsManager() constructor
Merge branch 'master' into new_well_formulation

Needed to avoid compile errors with updated opm-core.
Fix bug in -= operator.
Removed dead code in test_block.cpp.
Added test for += and -= operators.
Add more checks to cover bug that was in operator -=.