[Groff] new project gideal

[Bernd Warken]

The new project `gideal' tries to integrate the roff language `ideal'
into `groff'.  It is positioned at `contrib/gideal'.

The preprocessor is named `gideal' from `gideal.pl', with the man-
page `gideal.1'.  This preprocessor is just in a testing phase for
identifying the `ideal' parts.  But the `groff' surroundings for
the installation are already ok.

The language will be documented in `ideal.7' - not done so far.

### example test.groff:

before
.IS
this is within
the first ideal part
.IE
outside
.IS
the number
is now 2
.IF
after

### result of `gideal test.groff':

before
### ideal part number 1:
1# this is within
1# the first ideal part
outside
### ideal part number 2:
2# the number
2# is now 2
after


Bernd Warken