Opentok

This update adds support for the `initial_layout_class_list` field in tokens.

This update adds version information to the User-Agent string for analytics (78)

This update adds proxy configuration as a feature of the OpenTok object. (thanks juandebravo!)

Here is an example of using proxy configuration:

python
from opentok import OpenTok

opentok = OpenTok(api_key, api_secret)
opentok.proxies = {
"http": "http://10.10.1.10:3128",
"https": "http://10.10.1.10:1080",
}
session = opentok.create_session()


The format for the proxy configuration is identical to the format used by the underlying [requests](http://docs.python-requests.org/en/latest/user/advanced/#proxies) library.

New archiving features:
- Automatically archived sessions -- See the `archive_mode` parameter of the `opentok.create_session()` method and the `ArchiveModes` class.
- Audio-only or video-only archives -- See the `has_audio` and `has_video` parameters of the `opentok.start_archive()` method.
- Individual archiving -- See the `output_mode` parameter of the `opentok.start_archive()` method and the `OutputModes` class.
- Paused archives -- When no clients are publishing to a session being archived, its status changes to "paused". See `archive.status`.

Other improvements:
- Adds Python 3.4 support

The default setting for the `create_session()` method is to create a session with the media mode set
to relayed. In previous versions of the SDK, the default setting was to use the OpenTok Media Router
(media mode set to routed). In a relayed session, clients will attempt to send streams directly
between each other (peer-to-peer); if clients cannot connect due to firewall restrictions, the
session uses the OpenTok TURN server to relay audio-video streams.

This version of the SDK includes support for working with OpenTok 2.0 archives. (This API does not
work with OpenTok 1.0 archives.)

The `OpenTok.create_session()` method now includes a `media_mode` parameter, instead of a `p2p` parameter.

For details, see the reference documentation at
http://www.tokbox.com/opentok/libraries/server/python/reference/index.html.