Properly implemented the code dumper. Dumps are now printed in a stream. The individual opcode and operand implementations no longer use printf()s.

Exported sieve-code-dumper from sieve-interpreter containing all code dumping related implementation. Now to remove all printfs....

Fixed bug in handling optional operands to opcodes that have no mandatory operands (0 is no longer a valid opcode)

The :flags tag introduced by the imapflags extension now attaches side-effects to the appropriate action commands.

Changed id_code for optional operands to signed and fixed a ext_my_id-related error in the vacation and copy extensions.

Removed part of the code duplication between address-part, match-type and comparator implementations.

Added support for externally adding tags to (possibly not yet registered) command. The copy extension now adds such a tag to fileinto and redirect.

Almost finished implementing the store action. But, I still get strange errors when the mail transaction commits. Mail is stored though.