builder: Add Utils module and use common error/warning/info functions.

Add a Utils module.  This contains common error/warning/info functions,
and also quote = Filename.quote.

Examine every existing call to printf/eprintf and change where
necessary so that:

 - error is used instead of eprintf + exit 1

 - warning no longer needs ~prog argument (it is added by Utils module)

 - any verbose output should go to stdout, not stderr

 - info is used to print general informational messages
customize: Add Customize_utils module and use common error/warning/info functions.

Add a Customize_utils module.  This contains common error/warning/info
functions, and also quote = Filename.quote.

Examine every existing call to printf/eprintf and change where
necessary so that:

 - error is used instead of eprintf + exit 1

 - warning no longer needs ~prog argument (it is added by Utils module)

 - any verbose output should go to stdout, not stderr

 - info is used to print general informational messages

Also, don't pass ~prog parameter around.  Instead we just get it from
the executable name.
v2v: Add Utils.warning and Utils.info that don't require ~prog parameter.
sysprep: Use common error/warning/info functions.
resize: Tidy up messages.

Add common error/warning/info functions.

Examine every existing call to printf/eprintf and change where
necessary so that:

 - error is used instead of eprintf + exit 1

 - warning no longer needs ~prog argument (it is added by Utils module)

 - any verbose output should go to stdout, not stderr

 - info is used to print general informational messages

Also, don't indent summary of changes.
sparsify: Add Utils module and use common error/warning/info functions.

This program needs quite a lot more work, in particular to make the
regular messages use 'make_message_function' instead of 'printf'.