Found with clang -Wstrict-bool.

Found with clang -Wstrict-bool.

perl -i -pe 's/unsigned int ([^,:;]+):1;/bool $1:1;/' **/*.[ch]

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

lib-sieve: Restructured result execution, so that all actions which involve mail storage are always committed before all others.

This way, a duplicate is only marked when the script execution succeeds, as required in the specification.

This change is bigger than I would have liked, so this needs to be tested more.

- Changed operand read functions to prove exec status return codes in stead of boolean.
- Restructured optional-operand, stringlist and string-match APIs to provide execution status (error code) upon failure.
- Corruption errors are only produced when the binary is actually corrupt. Normal failures should never cause a recompile attempt anymore.
- Simplified optional-operand API.
- Cleaned up test command implementations that use the string-match API.

Fixed logging of mailbox names. It logged the converted mUTF7 version in stead of the original UTF8.

Restructured store action implementation to properly handle an attempt to store (keep) a message in the folder it originates from.

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.