Fixed the Qt backend "underlying C/C++ object deleted" bug. (Bug #1359249)
Applied Vasily Sulatskov's Qt Navigation Toolbar Enhancement. (Patch #1452234)
added halldors and norberts inter funcs
applied pearus linalg patch
Aspect-ratio handling noted in API_CHANGES
More aspect-handling cleanups; new axis('image') mode.
Updated CHANGELOG for recent aspect ratio handling changes.
Another increment of aspect ratio handling; make polar plots stay circular.
minor tweak in kwargs for fill example
Changed isinstance(x,str) to is_string_like(x)
