Dovecot core doesn't have copyright notices in header files.

lib-sieve: Renamed sieve_runtime_flags to sieve_execute_flags and made these available to result execution.

Included scripts now execute in the context of the inner parent foreverypart loop.

Needed for test suite.

When the program crosses the boundary of the current jump somehow, the program is terminated and a corruption error is returned.

Also cleaned up the surrounding code a bit.

- Added sieve_global_extensions setting.

Major rework of envelope address handling: a normalized version of the envelope addresses is maintained in the message context and message context is now also available during action execution.