Revert "loop in reverse order - this is a better search path"
This reverts commit
35e60acecf2f2657a3fd53f89053de9e57a0d7fe.
Doesn't actually seem to help that much.
error fixes; tried interior but doesn't work (EINSTAB) and docs say cannot cope with dense columns of which our X_minimum is one
wip lp seems to work so far...