Removed code duplication between testsuite and commandline tools. Also restructured source code of the tools.

Merged mail-raw implementations of sieve commandline tools and the testsuite, thus removing duplicate code.

Made lda plugin properly refer to the main script as 'main script' and not the basename of the sieve file (which is of no interest to the user for the main script).

Implemented implicit keep to execute when not canceled or when the preceeding action execution fails.