Endpoint scaling and hysteresis for gwseg.

Activation of eps and hysteresis treatment for gwseg. Also some
additional initialization.
Provide dependency information for opm-benchmarks
Depend on Boost::iostreams

The benchmark library uses Boost::iostreams to do decompression. Since
we only scan for the Boost dependency once, this submodule is added to
all of the projects in order to have a coherent dependency on Boost.
Uniformly raise Boost version requirement to 1.44

Commit 70505ff raised opm-core's "Boost" requirement to version 1.44
in order to reflect the requirements of the opm-parser module.  This
commit propagates that requirement to all other known modules.
Reformat prerequisite file according to convention

This commit makes a few adjustments to the white-space of file
'opm-parser-prereqs.cmake' to honour the conventions of the other
*-prereqs.cmake files within the OPM project's module suites.

No functional changes.
Depend on Boost.Iostreams

The benchmark library uses Boost::iostreams to do decompression. Since
we only scan for the Boost dependency once, this submodule is added to
all of the projects in order to have a coherent dependency on Boost.
Fix mis-merge.

In propagating the requirements for opm-benchmarks to the other
modules I accidentally removed the 'opm-parser' prerequisite (see
commit 86439d6 for details).  This commit restores that prerequisite.
Restore C++-11 checks

While reformatting the parser-prereqs file I accidentally replaced
the feature search 'CXX11Features' with 'CXX10Features'.  This
commit fixes that blunder.
Allow direct interpolation of props with new parser.

After transitioning to use the new parser, the SinglePvtDead class was never
used even when the 'samples' argument used to control usage was zero or negative.
The resulting construction of SinglePvtDeadSpline objects was then failing.

This change adds a new constructor to SinglePvtDead, and restores the ability
to control spline usage with the samples argument.
Merge pull request #503 from bska/503_cmake

[CMake] Propagate Boost.Iostreams to all modules
Merge pull request #504 from atgeirr/allow-no-spline-new-parser

Allow direct interpolation of props with new parser.
Defer searching for opm-parser

The "opm-parser" module is expected to become dependent upon the ERT
library.  Defer searching for the parser module until we've
established whether or not ERT is availble.

Suggested by: @andlaus
Elucidate description string for opm-parser.

The 'opm-parser' module is (currently) designed to parse ECL-type
simulation models.  Reflect that fact in its description.
Merge pull request #495 from osae/endscale

Endpoint scaling and hysteresis for gwseg.
Merge pull request #505 from bska/prereqs-nit

Fix a few nits in "opm-core-prereqs.cmake"
Suppress warnings from included istl code.

This is done using #pragma GCC and works also in clang.
Suppress unused argument warnings.
Changed open / close behaviour of well_controls:  1) well_controls has an explicit open_close flag. 2) Will NOT flip current value to change open|close status
Merge pull request #507 from joakim-hove/well-controls-open-close

Changed open / close behaviour of well_controls
Remove warning pragmas.

They are only available on gcc 4.6 and newer, and clang.