useorocos: Correctly log dependencies
useorocos: Fix typegen options when generating headers

The logic that produces ORO_TYPEGEN_HEADERS_IMPORTS ensures a
leading space. This confuses CMake's execute_command() output which
causes typegen to produce odd errors.

Typegen expects the -i import option before the project name.
cmake: fix cmake error if DEPS list is empty

Signed-off-by: Ruben Smits <ruben.smits@intermodalics.eu>
Replaced the ServiceRequester warning on connection of owner-less OperationCallers with a debug message
Fix https://github.com/orocos-toolchain/rtt/issues/25.

Signed-off-by: Johannes Meyer <johannes@intermodalics.eu>