plugin XEP-0166: new trigger point + coroutines + helper methods: - a new `XEP-0166_initiate` async trigger point is available - `initate` is now a coroutine - `jingleSessionInit` in applications and transports handlers are now called using `utils.adDeferred` - new `getApplication` helper method, to retrieve application from its namespace - new `getContentData` helper method to retrieve application and its argument from content