[Groff] new, new, new

[Werner LEMBERG]

Dear friends,


I've finally committed various new requests and a new escape:

  .  dei xx yy

     Define indirect.  The sequence

       .ds xx aa
       .ds yy bb
       .dei xx yy

     is equivalent to

       .de aa bb

  .  ecs

     Save current escape character

  .  ecr

     Restore escape character saved with `ecs'.

  .  \B'anything'

     This is an analogon to `\A': If _anything_ is a valid numeric
     expression, return `1', and `0' otherwise.

tmac.trace will now use .dei, .ecs, and .ecr to be independent from
the escape character.

Please test!


    Werner