Add test for rectangle path optimization with non rectilinear pen

This fails on pdf/ps.
pdf: fix rectangle stroke with non rectilinear pen
Add test for paint with alpha and clipping bug

Add test case for https://bugs.freedesktop.org/show_bug.cgi?id=68382

Something has regressed in the recording surface. All the recording
surface based backends lose the alpha from the paint_With_alpha.
ps: remove duplicate /Interpolate from image dictionary

http://lists.freedesktop.org/archives/poppler/2014-January/010748.html
Merge branch 'master' of git://anongit.freedesktop.org/git/cairo