Update Linux audio device sharing instructions

Ignore-this: 2a1c825373794c4978f5213f14c280ae

darcs-hash:20100531150714-58252-311638c735b3c4a6bcd9cb69ebef30f4080aa31a
Added ability to select PortAudio revision

Ignore-this: ef4a8c02fdf81dd3230269093c449906

Also rised it to 1433.

darcs-hash:20100531134012-56b4d-8b7e8096238781c15283f146fa4d28ae1eb0b5bf