This routine allows one to read MATLAB MAT-files in IDL. I've only
tested it on very specific .mat files so far, and not all variable
types are supported yet. However, the code is written in such a way
that one should be able to easily extend it so that it reads the other
objects MATLAB can store in a .mat file. If you'd like me to add
something, send me a .mat file and I'll try to make it work.

This routine only reads Level 5 .mat files [1] - it doesn't read
HDF-based MATLAB format.

Usage:

PRO load_mat, <filename>, <path>, STORE_LEVEL=store_level, $
              VERBOSE=verbose, DEBUG=debug

By default, it will create the variables on the $MAIN$ level. To have
the routine only create variables in your program's context, use
STORE_LEVEL=-1 in your program. See the (undocumented) IDL function
ROUTINE_NAMES for more information [2, 3].

[1] http://www.mathworks.com/access/helpdesk/help/pdf_doc/matlab/matfile_format.pdf
[2] http://www.physics.wisc.edu/~craigm/idl/down/routine_names.pro
[3] http://www.idlcoyote.com/tips/access_main_vars.html