configure: fix all except one warning produced by shellcheck

thanks to @bska for pointing this tool out!
Merge pull request #63 from bska/063_cmake

Synchronise build system with opm-core
Merge remote-tracking branch 'upstream/master' into opm-parser-integrate
Use EclipseWriter from opm-core

Note: The interface here requires opm/opm-core#424.
Merge pull request #52 from andlaus/write_binary_ecl

write out the reservoir state to the eclipse binary format
Merge remote-tracking branch 'upstream/master' into opm-parser-integrate
Fixed sim_fibo_ad, by adding EclipseWriter