New class MinpvProcessor, and test.
Add new constructor, that can handle MINPV processing.
Documented MinpvProcessor.
Change loop order.
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
Use syntax for std::array which works with GCC 4.4.
Merge pull request #635 from bska/fix-perm-assignment

Fix permeability assignment
New free function thresholdPressures().
Add new file.
Fix minor typo in comment.
Merge pull request #637 from atgeirr/add-minpv

Add MINPV processing to GridManager
assignPermeability: Remark on storage order

Clients expect column-major (Fortran) ordering of the contiguous
"permeability_" array so that's what we create despite "tensor"
being row-major.

Suggested by: [at] atgeirr
Add facility for accessing active subset of global data array

This commit introduces a fairly general mechanism for accessing the
active subset of a global grid (property) array.  Essentially, this
takes on the role of translating the active cell index through the
"global_cell" mapping when accessing, e.g., the net-to-gross data
value.

The primary component is class template

    Opm::GridPropertyAccess::Compressed<DataArray,Tag>

which implements a read-only

    value_type operator[](const int c)

that encapsulates and performs the compressed-to-global cell index
translation.  Template parameter "DataArray" is intended as a policy
parameter that for instance wraps access to a "GridProperty<T>" from
module opm-parser (with a fall-back default value if the data is not
specified on input).  The "Tag" parameter is a provision for type
safety--e.g., to prevent passing a region ID into a function that
requires a porosity value.