Item12781: Item12782: improvements to configure template parser

This one fixes an oversight in the previous fix for ={$foo?bar}= expressions
(a regex that was modified without updating the variables used to refer to its
capture groups), and fixes =<#foo></#foo>= type blocks by dealing with nested
blocks in a sane way.


git-svn-id: http://svn.foswiki.org/trunk/core@17342 0b4bb1d4-4e5a-0410-9cc4-b2b747904278