API change. Rather than passing the driver options as single "key:value"
string, we have a slot for each in ao_append_option()

corresponding documentation changes, harmonized ao_append_option()
definition in the header and docs, plus some other doc fixups.


git-svn-id: http://svn.xiph.org/trunk/ao@1119 0101bb08-14d6-0310-b084-bc0e0c8e3800