Drop repetitive -address from parameter names
Add --reply-to option to run-command-notify
Make mandatory command line arguments positional

Subject and sender must always be set, so make them positional
arguments.

The destination address(es) (--to) is/are also mandatory, but there can
be many of those. For now that remains an explicit option.
Split __main__
Add option to always send notification e-mail
Rename run-and-notify script
Give examples descriptive file names

Closes #2.
Allow AZs, ELBs and termination policies to be expressed as one or more

This makes list syntax superfluous when a single element is being used.
Allow definitions without a user-data field, again...

This has been broken since 5dbe0f68, when manifest validation was
introduced.
Remove references to demo-X

Examples were renamed to descriptive names in bca54e2f, but they were
still referred by their former labels in places.

Still fixing #2.
Move translation and transform constructs to own modules
s/append_to_key/append_to/
Split out validator for roles

Translation currently performs validation, but we'll want to validate
input independent of translation/transformation for API calls.
Manifest module *is* a validator
Drop ugly ~defaults~ feature from _translate

The function already takes a destination parameter that can be used to
inject defaults.
It turns out ':' is not allowed in these names...

Still #2.
Add a config module to hold configuration information

This is so that this information can be shared across modules without
ceremony.
Drop unused import
Reuse "common" functions
Reduce indentation