Quote possibly empty variable to avoid error message

On RedHat 6.4 workstation the module doesn't find the necessary system
information, and gives an error message when the last parameter to the
string function is not present.
Read /etc/system-release if others not parseable
Corrected mismatched if-else-endif arguments
Merge pull request #51 from rolk/051_distrib

Fix bug in reporting of system release (on RHEL 6.4)
Add test data to be used for testing upscaling binaries
Add test for upscale_perm

This test runs upscale_perm on a test model to see if it runs without
errors. Output is written to file, so that the results can be compared
to a reference solution in a later test.
Add application that compare two result files
Add test for upscale_perm

This test is twofold: First it tests if upscale_perm runs, and then compare
the solution with a reference solution by using the binary compare_upscling_results.

Documentation on how to add new tests is included.
Merge pull request #54 from laods/add_tests

Provide test for upscale_perm
Remove executable bit on input (data) file

Input data does not need to be executable, so remove the executable
bit on platforms where it matters.
Merge pull request #55 from bska/devel

Remove executable bit on input (data) file
Testing upscale_perm: Change to periodic BCs for test on PeriodicTilted.grdecl
Add grid models to be used for testing upscale_perm
Add new reference solutions for testing upscale_perm
Add more tests for upscale_perm

Also write a macro for testing upscale_perm on different models.
This change makes it easier to add more tests and to keep the code tidy.
fixed: resize arrays before insertions
Merge pull request #57 from akva2/resize_arrays

fixed: resize arrays before insertions
changed: reprioritize material properties from .grdecl

only take PERMX and PORO as elastic material properties as last resort

requested by kari b. skjerve through email
Merge pull request #58 from akva2/reprioritize_material_props

changed: reprioritize material properties from .grdecl
Chop test model 'hummockyexample.grdecl'

This reduce the computation time considerably.