first cut at refactor for issue 11

incomplete & untested
Testing pull request
setting locale for currency operations
Fixing display bug in experimenter dashboard. Fix #14
minor refactor to django signals usage

adding explicit logger.exception for errors in preparation for upcoming
__traceback__ support in send_robust responses
initial nginx and uwsgi config for issue #4
minor nginx and uwsgi config tuning
forgot to rename uwsgi supervisord program name
fix deploy permissions on virtualenv path
switch to nginx / uwsgi deployment
add dispatch_uid to core signal receivers

otherwise, update_daily_experiments is being signalled twice, causing
daily experiments to advance two rounds at a time.
haproxy config for vcweb app & sockjs
add haproxy config for sockjs

The timeout tunnel directive is essential for maintaining websocket
connections, tune as needed.

also changing vcweb-sockjs to bind to /websocket/participant and
/websocket/experimenter so haproxy can properly dispatch /websocket
requests to them
Refactoring Update Round Param Value code
Merge pull request #16 from alee/issue-11-refactor

refactor for issue #11
fix haproxy.cfg server timeout

use_backend sockjs *must* be listed before any use_backend vcweb so that
sockjs requests don't get dispatched to the vcweb app server