Revert "Keep influence items by default when loc. widening is active"

This reverts commit 176e369aaf4b7bb6453552491a77636ecf393ac2.
Revert "Add support for keeping influences in the solve function."

This reverts commit 220e6cc1fc6e0762168d278f87bc9b9d2ea6ff87.
Anticipate scheduling of widening points.

It may improve precision. It has the same effect of keeping influence
lists (the two commits previously reverted), but it simpler.
Change name of two of solvers for consistency reasons
Revert a patch for localized widening which is not needed anymore