fixed a visibility xlabel prob
added blitting to qtagg, not quite done
fixed bug #1523585: skip nans in semilog plots
fixed numerix to import rand, randn from numpy
added missing check for win32
classic to new-style classes
convert from classic to new-style classes
PDF: minor cleanups
PDF: attempt to provide mathtext support (very hacky, doesn't work perfectly)
backend_agg: Allow saving pdf files