To have both order from the GCS and drone messages in logs
So that it's possible to analyze the complete exchange between QGC and the
drone.

- Add a signal emitted by writeBytes of each LinkInterface
- Connect this signal to MAVLinkProtocol::logSentBytes in LinkManager
- MAVLinkProtocol::logSentBytes will parse and log messages sent from
  QGC

qobject_cast is times faster dynamic_cast for objects that
inherit QObject. also, use auto keyword to not duplicate
class names.

Use QHostAddress(string) instead

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

Signed-off-by: Patrick José Pereira <patrickelectric@gmail.com>

Fix TCP disconnection problem.

Prevent shutdown ordering crashes

This mechanism automatically queues data into the correct thread where necessary, otherwise the method is invoked directly with low overhead.

At the same time remove the UDP socket event workaround. It is not a problem.

Signed-off-by: Tomaz Canabrava <tomaz.canabrava@intel.com>

- Pervasive change to automatically connect to known board types
- Lots of additional changes along with this:
- More exposure of objects/properties to Qml
- Much restructuring in LinkManager and LinkManager clients

- Pervasive change to automatically connect to known board types
- Lots of additional changes along with this:
- More exposure of objects/properties to Qml
- Much restructuring in LinkManager and LinkManager clients

- Pervasive change to automatically connect to known board types
- Lots of additional changes along with this:
- More exposure of objects/properties to Qml
- Much restructuring in LinkManager and LinkManager clients

Link ids were being used interchangeably with the mavlink channel for
the link. Link ids handed out as a numerically increasing integer. Once
the counter went past MAVLINK_COMM_NUM_BUFFERS all hell would break
loose and cause memory corruption.

Also fixed a typo (copy/paste error) in the TCP link settings loading where it was using the UDP port as the default value instead of the TCP port.

Moving methods from MainWindow to QGCApplication so that more things
can run without a window. Helpful for testing.

Centralize all connecting and disconnecting of links through
LinkManager::[Connect|Disconnect]Link api. Connect/Disconnect no longer
allowed through LinkInterface. This allows creation of new
LinkManager::setConnections[Suspended|Allowed] methods to disallow
connections as needed.

This api doesn’t make any sense given the fact that LinkInterface
signals bytesReceived with the bytes in the signal. Also the reason why
it is never called!

This way the delete happens on the right thread.

Fix execution context of thread routines - note that this is not quite the architecture the Qt folks intended, but as they admit its the consequence of their architecture.

Also commented out noisy serial link error output