minor cleanup in find_new_facets
fix for volume computation

when using a unimodular mother the key was not adapted what lead to
incorrect results in non-homogenouse settings
allow to change back from recursive pyramids

Some scalar products are computed again to get the generators in the
hyperplanes returned from recursiv pyramids.
Possible improvement: get that data from the subpyramid.
get GenInHyp information for pyramids