Simplify setting of flag that indicates shared object

Instead of having the name of the module set for each flag, use the
available standard option. Mixing shared objects and static libraries
in the same build is not a very realistic scenario anyway.

This enables us to call configure without actually having a particular
module; the script may then be used on a group level.
Merge pull request #12 from rolk/012_configure

Update CMake scripts to commit f6d44238 from opm-core
Adapt to changed include paths for some opm-core headers.
Merge pull request #13 from atgeirr/make-io-subdir

Adapt to changed include paths for some opm-core headers.
Add dependency on dune-geometry

This makes dune-cornerpoint find header files from dune-geometry
and fixes issue #15
Merge pull request #16 from laods/release/2013.03

Add dependency on dune-geometry
Don't probe for umfpack with cholmod unless latter is found
Include standard math runtime library when linking numerics
Enable CMake < 2.8.5 clients to report Git version
Allow subdir builds with dunecontrol

dunecontrol will check for a dune.module file to regard the directory
as containing the module. If we put this is a sub-dir of the source,
it will get confused, so we shouldn't. There shouldn't be any
conflicting use-cases, as one cannot have several modules in the sub-
directory of one source (!?).
Don't search in architecture-irrelevant directories

If we are on a 64-bits machine, there is no point in searching lib32
and conversely. Quite the opposite, it can only end badly if a library
is actually found in the wrong architecture directory.
Test strings on length before content

A substring can of course not be longer that the full string. Also fixes
problems with CMake-versions that doesn't handle out-of-range parameters
to the SUBSTRING sub-command.
Search for uppercase variants of the package vars as well

For compatibility with packages that believes that every variable
should be in uppercase, we try this variant when adding relevant
variables to the project.
Use camel-case in SuperLU's name

Originally, I added FindSuperLU with uppercase since the variables it
returned had that case. Now the scripts should be patched so that it
searched for uppercase amongst the variables as well, so the module
name can retain its original case (and for compatibility with DUNE)
Enable debug tracing when finding modules
Allow variables from indirect dependencies to bubble up

The previous implementation was a function, which although OK from an
implementation standpoint -- the local variables doesn't pollute the
global namespace -- would not allow variables that were set in indirect
dependencies to bubble up to the main module. This is a problem for
modules which are dependent on configuration variables to be present.
Abstract into common version and parameterize
Use our own find routine recursively

Don't use bare find_package in OpmPackage when we have already written
OpmFind to take out the worst warts.
Add MPI dependency for dune-common

mpihelper.hh needs to know HAVE_MPI in the same way as the compiled
library in order to generate a consistent interface.
Only use MPI if explicitly enabled

Running with MPI on a regular workstation will probably not increase
performance, so this should be disabled as default.