Allow to search for multiple libraries in package

Some packages are split up in several library files, where each of them
doesn't have their own CMake find-module. So we cannot put this list in
the prerequisites. Unlike the headers, where we just add the directory,
all the libraries must be explicitly named on the link line. Thus, we
should allow to specify more than one name in the lib parameter.

The first name specified is designated as the "primary" library and is
assigned to the _LIBRARY variable; the others occur in _LIBRARIES as if
they were prerequisites.

Note that the build system cannot replicate this setup itself; it always
assumes that we are building (at most) one library from the source
files.
update packaging
Only add option for shared libraries once

The way the test was done previously, it was added for *every* option
after `--enable-shared`, not only that one.
Added method equals in BlackoilState.hpp
Added test with accompanying data for Blackoilstate::equals()
use a fully qualified source0 url
Allow to search for multiple libraries in package

Some packages are split up in several library files, where each of them
doesn't have their own CMake find-module. So we cannot put this list in
the prerequisites. Unlike the headers, where we just add the directory,
all the libraries must be explicitly named on the link line. Thus, we
should allow to specify more than one name in the lib parameter.

The first name specified is designated as the "primary" library and is
assigned to the _LIBRARY variable; the others occur in _LIBRARIES as if
they were prerequisites.

Note that the build system cannot replicate this setup itself; it always
assumes that we are building (at most) one library from the source
files.
Added CMake find modules opm-parser and cjson
Added opm-parser-prereqs.cmake
Updated modules for Findcjson and Findopm-parser
Updated modules to find Opm-parser
make redhat packaging compatible with el5
Merge pull request #417 from rolk/417_shared

Only add option for shared libraries once
Replaced include math.h with cmath, and changed from fabs to abs. Fixed an error in the testfile, a filename was wrong
Merge pull request #419 from flikka/blackoilstate-equals

Blackoilstate equals function, with tests and data
Merge pull request #416 from rolk/416_lib

Allow to search for multiple libraries in package
Merge pull request #418 from joakim-hove/cmake-find-opm-parser

Add cmake capabailities to locate opm-parser and cJSON