The water/gas pressures are only calculated if woc and goc lies within
the reservoar
The water/gas pressure is set to -inf when woc and goc is above or below
the reservoar.
Fixes issues pointed out in the PR comments
FindQuadmath: add -fext-numeric-literals if the compiler supports it

this is required for GCC >= 4.8 to support the 'Q' suffix for floating
point literals (which are used in the quadmath.h header)

In order to prevent compilers which eat the flag but do not support it
from complaining constantly, it is tested for with "-Werror" enabled...
CornerpointChopper::writeGrdecl(): Write fewer items per line

This is in preparation of increasing the vector output precision to
reduce the impact of rounding errors in subsequent upscaling.  The
change impacts floating-point vectors only.

Background: The ECL simulator stipulates an upper bound on the
number of characters in a record (i.e., one line) and while we don't
have such limits, there's no reason to emit lines that can't be
input by other tools.
CornerpointChopper::writeGrdecl(): Increase vector precision

This commit increases the precision of the (floating-point) vector
output (e.g., permeabilities) from method writeGrdecl().  This
reduces the impact of rounding errors when the sub-set sample is
output to disk for subsequent processing (e.g., property upscaling).
New class MinpvProcessor, and test.
Add new constructor, that can handle MINPV processing.
Documented MinpvProcessor.
Change loop order.
Merge pull request #632 from bska/cpchop-precision

Increase precision from CornerpointChopper::writeGrdecl
Merge pull request #630 from totto82/fix_init_spe9

The water/gas press. are calculated only if woc/goc is within the reservoar
Merge pull request #631 from andlaus/add_-fext-numeric-literals

FindQuadmath: add -fext-numeric-literals if the compiler supports it
Fix semantics of permeability assignment

Calling code relies on permeability tensors being stored in column
major order (row index cycling the most rapidly).  Honour that
requirement.  The previous assignment implied row major ordering
(column index cycling the most rapidly).  This, however, is a
pedantic rather than visible change because the surrounding code
enforces symmetric tensors whence both orderings produce the same
results when the array is viewed contiguously.
Remove obsolete comment

This comment was needed when the code was first developed, but
subsequent development has rendered it obsolete.  Remove it to avoid
confusion.
Simplify diagonal component thresholding

This commit switches the assignment

    diagonal = max(diagonal, minval)

to using a reference in the "diagonal" expression.  This guarantees
that the indexing is done once which eases maintainability.  While
here, replace the hard-coded dimension stride ('3') with the current
run-time dimension.  This is mostly for symmetry because the overall
code is only really supported in three space dimension.
Currectly handling GOC below and WOC above the reservoir The phase pressure of water and gas is set to inf when WOC and GOC is above and below the reservoir. This make sure the minimum saturation values are picked for these cases.
Remove unneeded const_cast.
Correct doc error (zcorn is also output argument).
Refactor set/getCellCorn() with private method.

Also const-ify everything that can be const.
Fix sign error in the specified oil pressures at at WOC and GOC
The oil pressure at the contact for the special cases:

contact	location	po(contact)
GOC 	above 	-inf
GOC 	below 	+inf
WOC 	above 	-inf
WOC 	below 	+inf