PyPlot ignores bbox="tight" when saving

I have searched the forums of stackoverflow and others to save a figure in pyplot without any padding, frame or axes/ticks. There seems to be an array of solutions, none of them seem to work on the Julia interface to PyPlot. Specifically, when I use
`savefig(outname, bbox_inches="tight", pad_inches=0.0, frameon=false, dpi=90)`
it seems to ignore completely both the bbox_inches and the pad_inches keywords. The saved figure
has exactly the same white unsymmetrical frame that all default figures have. `frameon` only seems to make it transparent, not to eliminate it.

Start by reproducing the Julia PyPlot savefig call with bbox_inches="tight" and pad_inches=0.0, then trace the savefig entry point to see how these keywords are passed. Done means the saved figure respects both options and the unchanged default padding is covered by a regression test.

Written by the indexing model from the issue text.