`test_all.sh` breaks when benchmark directory has spaces

[SaswatPadhi]

Something like test_all.sh -b "fancy benchmarks" fails with a ton of weird errors, because bash sucks. Although loopinvgen.sh is more tolerant to spaces in filenames, I haven't tested it very thoroughly.

It would probably be better to get rid of bash altogether (or just use it for StarExec builds), and instead write Python scripts: loopinvgen and test_all. The script execution time is anyway negligible. The main reason why we use these scripts is because there are various binaries invoked at different stages, and bash was a natural choice. But now that both these scripts are 250+ lines long, it would be better to use a (at least slightly) saner scripting language, like Python.