[WIP] ProcessorBase multi-threading

[WIP] Depends on !89 (merged) .

Add a ThreadedBaseClass that ProcessorBase inherit from.

It allows the computation of the ProcessorBase::process(...) to be performed in a separated thread. Threads aren't instantiated/killed but instead are put to sleep waiting for new CaptureBase.

ThreadedBaseClass API is rather simple :

• Constructor with argument max_frequency allowing the user to set guess what, a max frequency at which the processor operates.
• run() to start the thread and so the processor.
• stop() allows to stop the thread and so the processor.
• isRunning() let the user know if the processor is running or not.

Finally it has the pure virtual function :

• executeImpl() where the derived class do its job.

src/examples/CMakeLists.txt

@@ -139,6 +139,10 @@ TARGET_LINK_LIBRARIES(test_processor_tracker_landmark ${PROJECT_NAME})
ADD_EXECUTABLE(test_processor_imu test_processor_imu.cpp)
TARGET_LINK_LIBRARIES(test_processor_imu ${PROJECT_NAME})
+# Processor ODOM 2D test
+ADD_EXECUTABLE(test_processor_odom_2d test_processor_odom_2d.cpp)
+TARGET_LINK_LIBRARIES(test_processor_odom_2d ${PROJECT_NAME})
+
# IF (laser_scan_utils_FOUND)
#     ADD_EXECUTABLE(test_capture_laser_2D test_capture_laser_2D.cpp)
#     TARGET_LINK_LIBRARIES(test_capture_laser_2D ${PROJECT_NAME})