Merge branch 'master', remote-tracking branch 'source/master'
Merge remote-tracking branch 'source/master'
fix derivative of effective relperm respect to concentration.
Merge pull request #44 from qilicun/fix_eff_relperm

fix derivative of effective relperm respect to concentration.
Merge remote-tracking branch 'source/master'
Fixed build.
Merge pull request #45 from xavierr/master

Fixed build
Using the well_controls_get_xxx() functions.
Merge pull request #46 from joakim-hove/use-well-controls-api

Using the well_controls_get_xxx() functions.
Added required dependencies on opm-parser and CJSON
Set the boost version requirement to 1.44 - and added cJSON dependency
Removed explicit cJSON dependency from opm-core
Added CJSON_INCLUDE_DIRS to OPM_PARSER_INCLUDE_DIRS
Raised the opm-core boost dependency to 1.44 to reflect parser requirement
If given build tree as Eigen3 root, find source

Eigen3 is a template-library, so we must compile the source code
directly together with ours instead of linking to a library.

If the build script gives us the location of a "built" Eigen3,
meaning a directory in which CMake has been run, locate the true
source directory from the cache entries.
Search after new Eigen3 versions in sibling dirs

If we have checked out a newer Eigen3 directory in a sibling directory
to ours, assume that this is because the system version is obsolete and
that we want to use this one instead.
Provide CMake find module for opm-autodiff

If the module root is not explicitly specified, the loading of its
configuration is delegated to a find module, which does a heuristic
search in known/surrounding directories. Most OPM modules use the
common logic in OpmPackage; this patch configures the search
specifically for opm-autodiff.
Only add linker option if it is not really there

This code is run unconditionally each time we do a reconfigure; if the
option is added at each time, they will accumulate (needlessly) on the
command-line, making it harder to inspect the log.
Document modules and structures in the build system

Give a brief description of each of the modules that comprises the build
system, and the suffices that is used to form a virtual structure of
variables for each project.
Terminology instead of Notation as section header

Notation implies that we are going to be given symbols which
represents values or such (which arguably could be true since the
path is a particular value, and from programming we are used to
multi-letter symbols perhaps also with whitespace, but it's a
stretch), but Terminology is more accurate, as this section
describes fits the definition better: it is a vocabulary of
technical terms.

Hat tip: @bska