RateConverter: add missing call to averageTemperature()

thanks to [at] bska for noticing this!
Merge pull request #247 from andlaus/RateConverter_remove_averageTemperature

RateConverter: remove the unused averageTemperature() method
FindERT.cmake: Look for libecl_well library
Merge pull request #253 from joakim-hove/FindERT-update

FindERT.cmake: Look for libecl_well library
fixed: dune-cornerpoint (now) needs the dune-common version information
Findopm-parser.cmake: Fix it up, next try

thanks to Arne Morten Kvarving, Bård Skaflestad and Roland Kaufmann
for the discussion.
add the boost::regex library as a prerequisite

this is required for regex-matching keywords. Once GCC 4.9 is the
minimum compiler version to be supported, this can be dropped in favor
of std::regex ...
Find-ewoms.cmake: update prerequisites
FindCXX11Features: check for a usable std::regex

and add a config.h variable in the opm-parser test.
use extended regular expressions in the test for std::regex

for some compilers (e.g., GCC < 4.9) the default is buggy and
opm-parser thus uses extended expressions...

thanks to [at]bska for digging this up!
fixed: ERT depends on libdl

this issue was triggered with static libs for ERT
Build system: mark ERT as REQUIRED

de facto, this does not change anything because opm-parser is required
and it has a hard dependency on ERT. It is good style to declare all
prerequisites explicitly in each module, though. Thanks to [at]bska
for the catch.
add support for the new DUNE-ALUGrid module

this is basically the dune-grid grid manager for ALUGrid properly
out-sourced into an own module. (it does not require an external
library anymore, so it simplifies the build quite a bit.) Also, the
DUNE-ALUGrid module has quite a few new features and performance
improvements compared to the old code from dune-grid. For details, see

http://users.dune-project.org/projects/dune-alugrid
ewoms: make it possible to use the dune-alugrid module instead of the ALUGrid manager in dune-grid
ERT: link to the threads library of the OS

this is required to make the opm-core build succeed if ERT was build
with -DBUILD_SHARED_LIBS=OFF . (without it, I get errors like

    /home/and/src/ert/devel/libert_util/src/thread_pool_posix.c:328: error: undefined reference to 'pthread_create'
make the regex test more thorough

it seems like the std::regex delivered up to gcc 4.8 has problems with
constructs such as ".+". (at least if they appear at the end of a
regex...)
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...
set CMake policies CMP0026 and CMP0048 to OLD

this is required for CMake 3.0 to stop it complaining that we access
the LOCATION target property and set the *_VERSION_* variables ourselves.
add check-commits target
fix opm-parser find rule

deals with the fallout of opm-parser #365 and #366