SimpleSnapRounder performs bogus noding

[strk]

I've committed a GeometryNoder class with r3593 with which doing some noding tests. If I try to use SimpleSnapRounder noder rather than the IteratedNoder (or SimpleNoder) I get a completely wrong answer on the simpest case:

LINESTRING(0 0, 10 10, 10 0, 0 10)

There's something deeply wrong in the code and the whole Noding interface is overly confusing (probably due to memory management not correctly ported).

[strk]

The problem here was with misuse. SimpleSnapRounder, as all snap-rounding noders using HotPixel class, can only work with a FIXED PrecisionModel. FLOATING precision models break HotPixel and thus all its users.

Will leave this ticket open until HotPixel is equipped with a control to throw IllegalArgumentException on a 0 scale.

[strk]

r3612 adds an assertion in HotPixel