Accept notes and agents scheduled more than one hour into the future.

Put events and properties under the argdef type-checking system.

Add a "pan" argdef type. (Use in all soundscapes that take a pan
argument.) Also a "package" type.

boodle-mgr.py: add "examine resource", "install with all dependencies",
"check dependencies are installed".

Package creation: skip garbage files and directories (.pyc, ~, .svn).
(Based on regex in an environment variable?)

Agent: add chan= argument to get_prop, set_prop, etc. (For consistency
with other methods.)

