Merge branch 'release/2.1.0' into develop
[BUGFIX] Allow sending string SSML docs via Rayo

Fixes #191
[BUGFIX] Ensure that joined calls on Asterisk do not have implicitly linked lifecycles

Previously, joinees would be hungup when the joiner exited the bridge.

Fixes #193
[CS] Pre-compile a regex
[BUGFIX] Send outbound calls through the dial plan to ensure post-bridge redirect works

Fixes #193
[UPDATE] Bump to 2.1.1
Merge branch 'release/2.1.1'