adding the ability to strip out part of your file names when doing automatic file matching between two directories

a first attempt at a more generalized report command that can handle one or two file paths and will search directories and generate multiple reports if needed

The move from optparse to argparse caused a regression: positional
arguments could no longer intermix with optional arguments.  This fixes
that. (As of Python 3.7, parse_intermixed_args solves the problem,
but we want to support 2.6, maybe 2.5.)

adding extra checks when variable data is loaded to prevent crashing and some cosmetic changes to html report output

added global and variable attributes to report pages; fixed bug in the io module that was causing global attributes to never be loaded; corrected the behavior for purple marking circles behind small numbers of mismatch points and added that behavior to some other kinds of mismatch plots

Old behavior was to raise an uncaught exception. Now it reports a warning and continues onward.

"glance info --parsable" now outputs the results in tab deliminated format, repeating the filename on each line, making it easier to parse programmatically. Additional fields may be added later!

At the moment only supports "info".  May add support for other formats later.

Put sort directly into for loop; don't bother with giving it a variable.
Use named argument instead of relying on positional one.

Returns how many files could not be read, to a maximum of 255 (since the exit code is 8 bit).
This allows other processes calling "glance info" to detect errors.

Previously output was ordered in whatever order the set happened to offer them in. This was not stable between different Python versions.  Ordered alphabetically(ish) should be more human friendly, and will simplify the tests.

Previously "glance --version" was treated as an error, and the process's exit code was "9".  Displaying the version isn't an error.