Soundfiler should have inLevel outLevel and mute

#865
"offset" parameter on AudioIn / AudioOut modules is confusing

#872
Merge branch 'new-xml-schema' of https://github.com/BirminghamConservatoire/IntegraLive into new-xml-schema
added new 'web' folder containing browser-based utilities:
 * api-client
 * project-browser
minor amends to xmlrpc_server files, in support of CORS/AJAX requests from browser-based client