Clarified events documentation.
Clarified events documentation.

svn path=/trunk/libavg/; revision=7575

yyd01245/libavg,yyd01245/libavg,yyd01245/libavg,yyd01245/libavg,scotty007/libavg,scotty007/libavg,th3infinity/libavg,libavg/libavg,libavg/libavg,scotty007/libavg,th3infinity/libavg,scotty007/libavg,hoodie/libavg,hoodie/libavg,th3infinity/libavg,libavg/libavg,hoodie/libavg,libavg/libavg,hoodie/libavg,th3infinity/libavg