Disallow the user of 'service' as option key

Because the services can be fed through TTS tags, 'service' needs to be
reserved for the user to specify which service to use.
Use italics more sparingly in UI

Removes the use of italics except for displaying some program output and
version strings.
Safer JSON loading from configuration database

This extra lambda glue between the configuration loading and json.loads
ensures that the string being loaded from the database is, indeed,
going to provide us with a dict (which later parts of the program rely
on).
Improve error handling on service restoration

Adds additional checks to make sure that the service options that the
user has stored in their configuration works for the current state of
the initialized service.
Simplify other dropdown existence checks

These all now use max(xxx, 0) as a shortcut to setting the dropdown.
Rename amplitude to volume in eSpeak service

This makes this service consistent with the others.
Rename _remember_values() to _get_all()

This function is now more general purpose, allowing form processing to
happen directly from the dict.
Fix for field state in mass generator

For the dropdowns here to have a value assigned, we must use the
alternate form using addItem(x, y).