Refactor reading routine with potential buffer overflow

[aradi]

Code produced by the NAG compiler was crashing at this point

[bhourahine]

Seems correct, but not sure if there is anything weird about the parameter files.

[aradi]

Should be fine now. Changed error message and eliminated all superfluous code path in nextLine()

[bhourahine]

Other than updating and possibly squashing, could you add a comment in the commit log to the effect that the nexline routine now only reads from a named file, as was never called with a unit.