unicode pretty working
re-enable different display for matrices and scalars
1x1 matrices are replaced with scalars on return to Octave (fix Bug 15)

added an objectfilter python function that gets called just before converting to Octave, can add other hacks like this in the future
clean up display and pretty, add disp (alias for pretty)
changed my mind on disp: it should do the same as display

not necessarily just call pretty()  (although display should eventually use unicode output)
make display easier to configure
for popen2 ipc, no need to reload headers everytime
python header cleanup