Fix testsuite in octave (tested in 4.8.2 under Windows) by properly escaping `\t` (like in MATLAB) by `\\t`
fix #401 mandrillaImage being reversed

Reversing the image if axis is invisible is not needed.
Manual test with R2011b and R2014b by commenting out `axis off` in test case.
Removed black background to allow visual control, if axis is really of.
Merge pull request #420 from PeterPablo/fix_#401_ACID_mandrillaImage

fix #401 mandrillaImage being reversed
Merge pull request #419 from PeterPablo/fix_#415_ACID_octave_new

Fix #415 acid octave
trailing whitespace