Mark `logplot` reliable
Mark `logplot` reliable

This is confirmed in Mac/Linux R2014a and R2014b.
What Windows does, I don't know, but I left a comment
such that we can track this if it should become an issue.

matlab2tikz/matlab2tikz,egeerardyn/matlab2tikz,egeerardyn/matlab2tikz,PeterPablo/matlab2tikz,matlab2tikz/matlab2tikz