Merged changes from Pigeonhole v0.3 tree.

doc/rfc/spec-bosch-sieve-debug.txt

doc/rfc/xml/reference.VARIABLES.xml

doc/rfc/xml/spec-bosch-sieve-debug.xml

doc/rfc/xml/spec-bosch-sieve-duplicate.xml

src/lib-sieve/sieve-result.c

src/lib-sieve/sieve-script-dict.c

src/lib-sieve/sieve-script-file.c

src/lib-sieve/sieve-script.c

src/testsuite/Makefile.am

src/testsuite/cmd-test-binary.c

src/testsuite/ext-testsuite.c

src/testsuite/testsuite-common.c

src/testsuite/testsuite-common.h

src/testsuite/testsuite-log.c

src/testsuite/testsuite-script.c

src/testsuite/testsuite-script.h

src/testsuite/testsuite-variables.c

src/testsuite/testsuite-variables.h

src/testsuite/testsuite.c

tests/extensions/include/execute.svtest