Set task name on Lollipop
Launch each VM into a new task on Lollipop
Document incompatibility with NDK 10c

The GStreamer SDK uses symbols that were removed in NDK 10c.
Move static variable into SpiceDisplayPrivate
Drop code to attach/detach JNI threads to JVM

All callbacks to Java run in the glib main loop thread, which is already
attached to the JVM.
Don't get global reference to SpiceCommunicator object

All callbacks to Java occur before SpiceClientConnect() returns, so
the local reference will still be valid.
Drop unused global variable
Drop unused declarations
Eliminate globals in JNI code