#14 Adding removeDevice method

[G. Roggemans]

This patch adds the removeDevice method to the INDI::BaseMediator. This allows to handle the removal of a device from a connected INDI server. For the removal of INDI properties the removeProperty method exists, but the removeDevice method was missing. As a result a client implementation had no clue if a device was removed from the server.

There was already a removeDevice method in the BaseClient class. This method only deleted the device from the devices list without a way for the client to handle this event. It was renamed to deleteDevice and now calls the added removeDevice method before deleting the device object so the client can properly handle the event.

Included are temporary patches for the tutorial client and the imager agent so these can be compiled without errors. Proper handling of the event should probably be added.

[Jasem Mutlaq]

Thanks for the patch, it's applied now in trunk!