Make linear interpolation default for saturation properties.

This includes relative permeability and capillary pressure functions.
The default has been to make a monotone spline from the given table
values and use a fine, uniform sampling of that. Now the default
is to use the tables as-is. It is still possible to use the spline
approach. For example in the class BlackoilPropertiesFromDeck one
may pass nonzero values for the 'pvt_tab_size' and 'sat_tab_size'
parameters, corresponding to how fine the spline will be sampled.
Merge pull request #497 from atgeirr/no-spline-default

Make linear interpolation default for saturation and some pvt properties.
Add handling of WGRUPCON to new-parser friendly WellsManager constructor
Merge pull request #500 from flikka/add-WGRUPCON

Add handling of WGRUPCON to new-parser friendly WellsManager constructor
Merge remote-tracking branch 'upstream/master' into opm-parser-integrate
SimulatorTimer: make it possible to base it on opm-parser's TimeMap

Since SimulatorTimer is a fairly shallow shim if using the TimeMap, it
can also be removed relatively easily. Having said this, that would
trigger _many_ changes in _a lot_ of places and I'm not motivated at
all to fight that battle as long as the old parser needs to be
supported. I thus decided that the best way is to add a "wrapper mode"
to SimulationTimer...