Fixed an issue creating file system asset stores on Windows.  Specifically, Windows doesn't support os.openvfs to get disk usage and size, so detect the platform version, and, if Windows, use a Windows API call to get this information.
Replace mutable default parameters
Simplify chained comparison
Fix spelling mistakes
Fix PEP 8 coding style violations
Remove redundant parentheses
Fix instance attribute defined outside __init__
Fix single-quoted docstring
Small CSS fixes
Tweak .gitignore to ignore more coverage files
Minor cleanup of Python client
Add metadata extractor plugin
This includes a change to allow node postinstall script to run on Windows.  This removes pathing inside of the postinstall instruction in package.json.  Node should have node_moudles/.bin in the current path when it executes these instructions, so this should do no harm to the linux deployment.  I have also added a few notes on installing to Windows to the documentation.  We probably want to add a warning that we aren't officially supporting Windows and it is use-at-your-own-risk.
Fixed formatting so that the added code passes unit tests.  Added a pragma nocover to the Windows specific code.
Added a warning that Windows is not supported or tested and to use at one's own risk.
As per discussions on how we don't really want to support Windows at this time, I've changed the capacityInfo function to just report that it doesn't know anything if an OS doesn't have statvfs (Windows).  Although not as nice as reporting the capacity, it avoids platform-specific code.
Changed the lack of support for Windows from a note to a warning; improved the wording.
Added a rest method to copy an item.  Added the abaility to copy a file to the file model.  Adjusted the gridFS and S3 assetstores so that duplicated files don't need to duplicate data.
Added tests for copying items and for some other cases that were not covered.  Fixed an issue in testing for blank metadata keys.  When downloading a multi-file item, I've added a sort parameter so that the files are in a predicatable order.
Fixed a python style complaint.