Workaround for graph bug

See http://wiki.theamazingaudioengine.com/graph-node-input-callback-bug
Adjusted playthrough channel's max allowed latency down to zero
Converted some errant tabs to spaces
Documentation fix and minor code cleanup
small fix to filtering section in guide
Merge pull request #19 from willpragnell/master

Small fix to filtering section in guide
Documentation fix
Fixed a potential black-hole state in input routine
Minor buffer safety adjustment in input routine
Avoid unnecessary reconfigurations on setting identical input channel selection
Apply Audiobus input port client format at more appropriate times to avoid transient format incompatibility problems
Fixed a typo in AEAudioFileLoaderOperation when assigning a channel map

Thanks to @RandomMao on the forum for catching this one
Fixed a circular reference
Improved track removal procedure