Added support for AVTransport eventing v. 1.01

Added support for AVTransport eventing v. 1.01 [1], so cling is compatible to gmediarender-resurrect, which already uses this version (https://github.com/hzeller/gmrender-resurrect).

[1] http://upnp.org/specs/av/UPnP-av-AVTransport-v1-Service.pdf