sdp.js: Check presence of msid and mstid before generating msid line
OwrMediaSession: Run object signal handler in cleanup stage

For on-incoming-source
docs: Add pipelines in the type of svg
Merge pull request #91 from zzoon/upstream2

docs: Add pipelines in the type of svg
owr: Don't use ercolorspace for ARM64 for now
added the possibility to export symbols for specific platforms from libopenwebrtc.exp

Syntax: <symbol> [if <host> [or <other host>]...]
added OwrWindowHandle gir type + annotations to owr_window_registry
added gen_jni.py, which generates Java bindings for Android using GIR and JNI
added OwrBridge JNI implementation
modified build to generate, compile, and link JNI files when building for Android
compile generated Java classes and create openwebrtc.jar and openwebrtc_bridge.jar when building for Android
Owr: Use videoconvert instead of ercolorspace on Android

Not all Android devices have NEON support, and videconvert will do the right
thing using ORC
owr/owr.c: Register gstnice as an ordinary gst plugin
bridge/Makefile.am: Use static libraries for openwebrtc-bridge

When requested, use as many static libraries for the bridge as possible
owr/Makefile.am: Add various files to CLEANFILES, and do cleanup
configure: Detect Android-specific things using a configure option

SDK, NDK, JAVAC, JAR, etc.
gen_jni: Overhaul build system

* Instead of building the JNI bindings inside libopenwebrtc{,_bridge}.so, build
  separate _jni.so libraries for those.
* Build the openwebrtc.jar and openwebrtc_bridge.jar files using autotools