v0.6.0-beta8

RELEASE NOTES

1. New Functionality
- Test runs ("dry runs").
- New "User Group / Experiment / Dataset" folder structure.
- Support for includes / excludes (file pattern matching).
- Upload invalid user folders checkbox now also works for user groups.

2. Changes in Appearance
- New Test Run toolbar icon.
- Refresh toolbar icon has been replaced with an Upload toolbar icon.
    The functionality is still the same (scan / re-scan folders and
    upload if not already uploaded).
- Changed field order in Settings Dialog's filtering panel to User, Experiment, Dataset.

3. Improved Functionality
- More efficient data folder scanning (previously, os.walk was being called twice,
    once to count files, and once to list them).
- More responsive to Stop requests: Settings validation now checks periodically
    for ShouldAbort().
- MyTardis URL testing during settings validation now uses the MyTardis site's API URL,
    instead of its About page, whose response time gives a more realistic indication of
    whether MyData will be able to perform adequately.

4. Bug Fixes
- If the user pressed Cancel from the Settings dialog after a failed settings validation,
   the settings were not saved to disk, but they were saved in memory.  Now they are
   rolled back when Cancel is pressed.
- For approved uploads via staging, ensure that the correct storage box can be reliably
  determined from the POSTed data.  (There is a related change in the
  https://github.com/mytardis/mytardis-app-mydata server-side app).
- Ensure that attempts to load settings from server can't raise a critical exception.
- Ensure that a "(Tentative)" IP address annotation isn't included in the local IP address
POSTed to the MyTardis API.
- Fixed bug in "Cancel All Remaining" when using POST upload method which meant that MyData waited until the current upload completed before canceling.