real/double mixing in SIGN calls

[Huite]

Gfortran is unhappy about:

RSIGN=SIGN(1.0,RBRANCH)

Since 1.0 is a float, and in this case RBRANCH is a double.

Easy fix is to e.g. specify a constant like D_ONE as double:

REAL(8) D_ONE
D_ONE = 1.0


RSIGN=SIGN(D_ONE,RBRANCH)

I think converting every real to a double would be fine at this point too.
Memory usage definitely isn't a problem anymore, but roundoff definitely is. I don't think it'll affect runtimes much either.