Although patch is rather big, it mostly consists of multitouch code
refactoring required to import EBM-solver implementation from OpenBSD
and of EBM-solver itself which is required for touch tracking.
"Touch tracking is a process of assignment of unique trackingID to each
initiated contact on the surface. Keeping the trackingIDs persistent
across multitouch reports requires solving of so called Euclidian
Bipartite Matching problem."
Tested by Greg V, Constantin Furst<constantin_AT_fuersten_DOT_info>
MFC after 2 weeks
PR 252236