dbus-ws-proxy

This builds on the new dbus role support to provide a minimal example proxy
between ws and dbus.

A client app is provided that asks the proxy to connect to libwebsockets.org
and proxy the drawing data from the mirror example there back to the dbus
client using dbus messages.
diff --git a/CMakeLists.txt b/CMakeLists.txt
index ba7dac7..8150f82 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -133,6 +133,12 @@
 	set(LWS_ROLE_DBUS 1)
 endif()
 
+# do you care about this?  Then send me a patch where it disables it on travis
+# but allows it on APPLE
+if (APPLE)
+	set(LWS_ROLE_DBUS 0)
+endif()
+
 if(NOT DEFINED CMAKE_BUILD_TYPE)
 	set(CMAKE_BUILD_TYPE Release CACHE STRING "Build type")
 endif()
@@ -686,15 +692,15 @@
 CHECK_LIBRARY_EXISTS(cap cap_set_flag "" LWS_HAVE_LIBCAP)
 
 if (LWS_ROLE_DBUS)
-	if (NOT LWS_HAVE_LIBDBUS)
-		message(FATAL_ERROR "Install dbus-devel, or libdbus-1-dev etc")
-	endif()
 
 	if (NOT LWS_DBUS_LIB)
 		set(LWS_DBUS_LIB "dbus-1")
 	endif()
 
 	CHECK_LIBRARY_EXISTS(${LWS_DBUS_LIB} dbus_connection_set_watch_functions "" LWS_HAVE_LIBDBUS)
+	if (NOT LWS_HAVE_LIBDBUS)
+		message(FATAL_ERROR "Install dbus-devel, or libdbus-1-dev etc")
+	endif()
 
 	if (NOT LWS_DBUS_INCLUDE1)
 		# look in fedora and debian / ubuntu place