Improved result execution and prevented failure on store action on dry run (with no specified namespace).

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....

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

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