Remove capybara-webkit gem.

The version no longer builds on Ubuntu 14.04 and a newer version seems to
require extensive code changes. Falling back to selenium for now.
Fixed `client_supports_http_basic_auth?`
Updated ext/tmc-sandbox
Fixed horrible JS inclusion mess. Wtf?
Fixed rake compilation rules for tmc-spyware-server.

Avoid unnecessary rebuilds, rebuild on rake spec.
Updated tmc-comet and rake tasks to compile and launch it.
Reduced submission page polling interval from 5s to 2.5s.
Updated submodules.
Fixed tests when machine timezone is not Helsinki.
Fixed comet support in tests.
Fixed checkstyle test.
(minor test renames)