Declarations for actual callback support code
First implementation of a private callback type
Added back in enable_shared_from this: callbacks must be able to extend the lifetimes of objects slightly
Callback infrastructure: get and work with callbacks the same way as properties
LavObject constructor: associate callbacks to our device
Reworked the callback support code to always use a background thread and thus be a more generic task system
Callback objects extend the lifetime of the object with which they are associated if they are expecting to fire.
Add a hypothetical callback to the metadata
Finished callback support code; objects have callback tables.

Works the same as properties. Exactly.
Numerous file object fixes
File node optimizes itself when reaching end of file and calls the callback
Keep callbacks from sending the task if they don't yet have handlers
Callback public API
File example uses callbacks to display message when file ends
Bindings generator refactoring and improving: almost handles callbacks and doesn't crash.