matplotlib Code

Fix running unicode_demo.py from backend_driver.py. (The -*- coding
line must appear before any non-comment lines).

Easy specification of default output format for cairo backend

Make cairo testing easier (partial)

Make backend_driver.py interruptable with Ctl-C

update backend_driver

Support for maskedarray alternative to ma

Add masked_demo.py to backend_driver.py.
This will help us check that changes don't break basic
masked array support in the plot command.

more units refactoring

some more units refactoring

added sameers xcorr patch