Flight Tasks: CMake/folder restructure (no code change)

put flight tasks in separate folder and create a lib for each
goal is to select tasks for targets (e.g. because of flash issue)

src/lib/FlightTasks/tasks/CMakeLists.txt

@@ -0,0 +1,50 @@
+############################################################################
+#
+#   Copyright (c) 2018 PX4 Development Team. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in
+#    the documentation and/or other materials provided with the
+#    distribution.
+# 3. Neither the name PX4 nor the names of its contributors may be
+#    used to endorse or promote products derived from this software
+#    without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+# COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+# OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+#
+############################################################################
+
+px4_add_library(flight_task
+    FlightTask.cpp
+    SubscriptionArray.cpp
+)
+
+add_subdirectory(Utility)
+add_subdirectory(Manual)
+add_subdirectory(ManualAltitude)
+add_subdirectory(ManualAltitudeSmooth)
+add_subdirectory(ManualPosition)
+add_subdirectory(ManualPositionSmooth)
+add_subdirectory(ManualStabilized)
+add_subdirectory(Auto)
+add_subdirectory(AutoLine)
+add_subdirectory(AutoFollowMe)
+add_subdirectory(Offboard)
+add_subdirectory(Orbit)