Configure the doxygen preprocessor to ignore __attribute__() strings.

http://taulabs.org/TauLabs/doxygen/flight/html/group___actuator_module.html shows a data structure ```__attribute__``` http://taulabs.org/TauLabs/doxygen/flight/html/actuator_8c_source.html shows that it's actually a ```Mixer_t``` data structure. 

http://www.rtems.org/wiki/index.php/Doxygen_Recommendations#GCC_Attributes details how to fix this behavior.