Acidtest: errors are displayed on stderr
Acidtest: errors are displayed on stderr

By using stderr for errors, they get highlighted in MATLAB (and at least QtOctave).
This makes errors stand out more.

nidrosianDeath/matlab2tikz,egeerardyn/matlab2tikz,LJeub/matlab2tikz,egeerardyn/matlab2tikz,miscco/matlab2tikz,matlab2tikz/matlab2tikz,matlab2tikz/matlab2tikz,okomarov/matlab2tikz,PeterPablo/matlab2tikz,okomarov/matlab2tikz,RPeschke/matlab2tikz