perl/t/10query.t: Perl 5.16.1 adds a '.' after "at foo line 123" so
adjust regexp in testcase to allow an optional '.' there.
(ticket#610)

git-svn-id: file:///home/xapian-svn/xapian/trunk@17039 6b2f1b92-a4f3-0310-943f-de3cbe41748b
matcher/selectpostlist.cc,matcher/selectpostlist.h: Check document
matches weight threshold before checking positional information,
which speeds up slow phrase searches (tweaked version of
positional-query-weight-check-first.patch from #394).

git-svn-id: file:///home/xapian-svn/xapian/trunk@17041 6b2f1b92-a4f3-0310-943f-de3cbe41748b
Makefile.am,jsonescape.cc,jsonescape.h,jsonesctest.cc,query.cc:
Add new $json and $jsonarray OmegaScript commands.

git-svn-id: file:///home/xapian-svn/xapian/trunk@17042 6b2f1b92-a4f3-0310-943f-de3cbe41748b
docs/omegascript.rst: Document $json and $jsonarray.

git-svn-id: file:///home/xapian-svn/xapian/trunk@17043 6b2f1b92-a4f3-0310-943f-de3cbe41748b