State History - Fixes to search interval

After a date picker was added to the ui, changes were
needed to the backend.

The code is still messy and "number of alerts" still shows
all alerts for that logfile, but this is better than before
403 errors return json if appropriate
Improve access_map in auth.py
Update debian/changelog
auth.access_map renamed to access_list
minor cleanup
CHANGES Updated
Added AUTHORS file
Renamed license file to COPYING
add: json backend to store user preferences

- json files are stored in userdata/
- sessions are now used, to keep the language preference
  - sessions are file-based and stored in sessiondata/, this can be
    easily changed
- userprefs.py manages the json files and provides methods to get
  the preferences and update them
add: rest interface for user preferences
add: unittests for user preferences
Bumped version number to 1.5.0
fix spacelab origine in CHANGES
Merge pull request #351 from matthieucan/fix

fix spacelab origine in CHANGES
userprefs: replace  theme hook by context preprocessor
remove session_file_path

If not provided, Django will generate at tmp one for us.
Oh and Travis seems not to like it.
Top navigation alerts are back to white

In a previous synchronization effort they were
made grey, but they are white on purpose so they
are more noticable by the user.
Merge branch 'master', remote-tracking branch 'upstream/master'
update message for saved preferences