Short term addition to the existing IUCr dataname recording restraints in the format used by the refienemtn program.

In our case, it will eventually be replaced (where possible) by terms from the restraint dictionary.

simlple example

DIST 1.55, .01 = C(9) TO C(10) 

DIST 0.00, .01 = MEAN C(1) TO H(11), C(1) TO H(12), C(1) TO H(12)