reorganized posix sitl launch scripts, reorganized mavros python test scripts (integration tests) and updated them for posix sitl, removed old and not working integration tests

integrationtests/setup_gazebo_ros.bash

@@ -0,0 +1,20 @@
+#!/bin/bash
+#
+# Setup environment to make PX4 visible to ROS/Gazebo.
+#
+# License: according to LICENSE.md in the root directory of the PX4 Firmware repository
+
+if [ "$#" -lt 1 ]
+then
+    echo usage: source setup_gazebo_ros.bash firmware_src_dir
+    echo ""
+    return 1
+fi
+
+SRC_DIR=$1
+
+# setup Gazebo env and update package path
+export GAZEBO_MODEL_PATH=${GAZEBO_MODEL_PATH}:${SRC_DIR}/Tools/sitl_gazebo/models
+export GAZEBO_PLUGIN_PATH=${SRC_DIR}/Tools/sitl_gazebo/Build/:${GAZEBO_PLUGIN_PATH}
+export LD_LIBRARY_PATH=${LD_LIBRARY_PATH}:${SRC_DIR}/Tools/sitl_gazebo/Build/msgs/
+export ROS_PACKAGE_PATH=${ROS_PACKAGE_PATH}:${SRC_DIR}