Now checks for missing TOPS or DEPTHZ in DXV etc. initialization.
Corrects required version and make Eigen3 download work.

At least on Debian requiring version 3.1 of Eigen3 is not sufficient
according to issue #25 the minimum version is 3.1.2. This patch fixes
the required version. In addition it skips the REQUIRED option passed
to find_package(Eigen3) to make the git download work.

Fixes #25.
Fix summary output, now contains output for all steps.

Previously, the summary output was rewritten for each step,
leaving only the last step's data in the summary data file.
Add summary output of bottom hole pressures.
Merge pull request #474 from atgeirr/throw-missing-tops-depthz

Check for missing TOPS or DEPTHZ in DXV/DYV/DZV initialization.
Removed erroneous comment.
Fix fallout from PR #474

The check introduced in PR #474 (commit ad899fc) means all decks
must supply valid depth data.  Update test decks accordingly to
restore "make test".
Merge pull request #483 from bska/fix-test-fallout

Fix fallout from PR #474
Merge pull request #478 from osae/endscale

Saturation table scaling and hysteresis.
Merge pull request #476 from andlaus/fix_eigen3_version

Corrects required version and make Eigen3 download work.
Merge pull request #481 from atgeirr/fix-summary-output

Fix summary output, now contains output for all steps.
Fix SimulatorTimer-related bug in EclipseWriter.

Since writeTimeStep() now gets called also before the first timestep is done,
the EclipseWellTotal::update() method was in error, always calling
SimulatorTimer::stepLengthTaken(). That method cannot be called if the
timer's currentStepNum() is 0, so that is checked for and intercepted.
The total rate in that case is of course zero.
Added SatFuncBase.hpp to CMakeLists_files.cmake
Merge pull request #486 from osae/fixCmake

Added SatFuncBase.hpp to CMakeLists_files.cmake
Fix initialisation warning.
Suppress warnings in unimplemented functions.

This prevents warnings from functions that are right now just
a throw statement. Also cleaned up a few whitespace issues nearby.
Moved explicit template instantiation inside namespace.

Clang requires this to happen inside the namespace of the class
(which is in the anonymous namespace) and issues an error diagnostic.
Suppressed some unused parameter warnings.
Removed unused argument from buildTracerHeadsFromWells().
Fix unused argument warnings.