Added _setFlag() to handle setting flags on all channels.
setFlag() now sets both input and output channels if both kInFl and kOutFl are set.
Previously it only set the input channel if both kInFl and kOutFl were set.
Other minor changes to prepare for integration into cwIo.
In cwMidi* replaced 'byte_t' with 'uint8_t'.
In cwAudioDevice* removed redundant 'device' prefix from function names.