Testsuite: added test_compile command to test compilation of scripts.

.hgignore

src/lib-sieve/sieve-script.c

src/lib-sieve/sieve-script.h

src/testsuite/Makefile.am

src/testsuite/cmd-test-fail.c

src/testsuite/cmd-test-set.c

src/testsuite/cmd-test.c

src/testsuite/ext-testsuite.c

src/testsuite/tests/compile/compile-examples.svtest

src/testsuite/tests/compile/compile.svtest

src/testsuite/tests/compile/redirect.sieve

src/testsuite/tests/compile/trivial.sieve

src/testsuite/testsuite-common.h

src/testsuite/tst-test-compile.c