matplotlib Code

partial cleanup of mlab and of the pylab imports from mlab

applied Goekhan's installation FAQ patch

add support for bz2 files per sf support request 2794556

Fix problem with polar grid lines by specifying the number of interpolation steps on a per-Path basis. This isn't really a public API -- it is intended for internal use only.

Use subprocess.Popen instead of os.popen to retrieve memory usage. os.popen* are deprecated in Python 2.6.

Make images handle invalid values as if masked.
A little cleanup and docstring addition to image.py was included.

get rid of 'U' in mode flag for gzipped files.

make default mode 'r' for gzipped files, since 'rU' apparently is not
supported in the gzip module (at least in python 2.5.2)

changed the default file handle to open in universal mode

Merge 6802 from 98.5 maintenance