doxygen documentation for pa_mac_core.h isn't showing up in html docs

[rossb]

There is great documentation in pa_ma_core.h but it isn't being outputted, see: http://www.portaudio.com/docs/v19-doxydocs/pa__mac__core_8h.html

It is missing an extra * at the first line of each doxygen comment I think. Eg should be:

/**

*/