Completed implementation of the relational extension.

README

...gins/comparator-i-ascii-numeric/ext-cmp-i-ascii-numeric.c

src/lib-sieve/plugins/regex/ext-regex.c

src/lib-sieve/plugins/relational/ext-relational.c

src/lib-sieve/plugins/relational/relational.sieve

src/lib-sieve/sieve-match-types.c

src/lib-sieve/sieve-match-types.h

src/lib-sieve/tst-address.c

src/lib-sieve/tst-header.c