Introduce \. as a NOP command. The purpose of this is to act as a

Introduce \. as a NOP command. The purpose of this is to act as a
zero-width delimiter between a macro invocation and text beyond it,
so that you can define (say) a macro which expands to a Euro sign
and then write `\eur\.2500' to avoid having space between the Euro
sign and the number.

git-svn-id: svn://svn.tartarus.org/sgt/halibut@3982 cda61777-01e9-0310-a592-d414129be87e