Clean up whitespace in main module

Brings this file to UNIX file endings and 4-space blocks.
Overhaul of Google service implementation

This brings this implementation in-line with the others, including
moving the path creation stuff for the caching directory out into the
paths module.
Overhaul of SAPI 5 service implementation

Brings in better checks for voices and more cautious file generation,
also making this code consistent with the other service implementations.
Remove filegenerator_run hook for all services

This function does not vary from service to service, so the burden of
implementing a service can be reduced by moving it to the main module.