Fix wrong max_score and max_public_score in ScoreType Sum

They weren't updated after having changed public_testcases from list to
dict. I also suppose that ScoreType Relative didn't get updated.
Some style improvements to the submissions table
Improve notification handling in CWS

Do not count them in the unread messages counter and show their subject
and text on the alert (instead of nothing...).
Fix previous commit
Fix the format of some dates in CWS
Merge branch 'master' of https://github.com/cms-dev/cms
Small style fixes
Use DateTime instead of Integer for timestamps in the DB

And Interval instead of Integer for time differences.
Small fix to previous commit
Fix various issues about contest-phases and timing in CWS

Display properly the per_user_time information, allow users to start
their time when they want (and not as soon as they log in), allow users
to do certain actions only during their per_user_time (the server
checked only that the contest was running...), give access to
communication and documentation also for users that didn't start yet,
add the server time on the interface and other minor fixes.
Fix some bugs caused by the Integer-to-DateTime change
Make the DateTime fields in the DB be in UTC instead of local timezone

This way we have no ambiguity on DST boundaries and it's easier to do
timezone conversions (we'll need this when we make CWS timezone-aware).

Also, the format in which datetimes are displayed in CWS is now
localizable. On the other hand, AWS displays (and requires as input)
datetimes in UTC in ISO format (with a space as separator).
Add my name in the copyright notice of files I have modified

And also fix doc/license.txt to assign the copyright of all files to all
of us "main authors", instead of splitting cmsranking out.

Change the Upstream-Contact of doc/license.txt to be the official ML.
Modify the way CWS stores a local copy of the submissions

CWS was using pickle.dump to store a local copy of the submissions, to
recover them in case of failure. It was dumping the ID of the Contest,
the ID of the User and the Task object, along with all the submitted
files. Now CWS stores just the ID of the Task (instead of the whole
Task).

Storing the whole Task object makes pickle fail because of some circular
references among objects, i.e. task == task.contest.tasks[i] for some i.
Pickle should handle them correctly (in my opinion), yet some bugs are
present[1].

This bug has been introduced by commit c7eb5bb. It wasn't present before
because, thanks to the lazy-loading of SQLALchemy relationships[2], the
contest.tasks attribute was never requested and, thus, never loaded.
This prevented pickle from trying to dump it and falling into infinite
recursion.

Fixes issue #16 (see that issue for more details on this bug).

[1] http://bugs.python.org/issue9269 (note that mike bayer, aka zzzeek,
    commenting on this issue is the author of SQLAlchemy)
[2] http://docs.sqlalchemy.org/en/rel_0_7/orm/loading.html
Don't show token column in task table in overview if tokens are disabled
Fix token handling in YamlImporter

Set default values to disable tokens.
Make DateTime.make_timestamp return floats with microsecond precision
Let "now" timestamps in CWS refer to the moment the request was received

Use a single datetime object, created as soon as we start handling the
request, in place of all "make_datetime()" calls (or similar).
Make AWS interpret missing arguments as "None"

Tornado discards all empty arguments in the requests it receives. This
makes it impossible for us to distinguish between "missing argument" and
"empty argument". I think that in the first case get_non_negative_int
should return the default value and in the second it should return None.

Since, using AWS, the requests always contain all arguments (possibly
empty) I'm changing the default behavior to consider the missing
arguments as empty (thus returning None), until we find a way to
distinguish between missing and empty.
Merge branch 'master' of https://github.com/cms-dev/cms

Conflicts:
	cms/server/templates/admin/base.html