This was some meticulously preserved relic of bad old DOS times used to block OS facilities to close an app.
Since this has been worked around at a lower level already the variable was essentially without function but some quite bad code depended on it.
Using that higher precision, interpolate at a higher granularity.
Further, truncate the target interpolation time to vertical blank boundaries to avoid producing temporal artifacts.
Fix issues caused by interpolation calculations being handled differently in multiple places (and fix cases where smoothratios were being thrown away only to be redone without checking all proper conditions).
Ensure ClockTicks changes do not break other targets (EKenBuild, VoidSW), but note any interpolation there is not similarly updated.
git-svn-id: https://svn.eduke32.com/eduke32@8050 1a8010ca-5511-0410-912e-c29ae57300e0
# Conflicts:
# source/build/src/build.cpp
# source/build/src/sdlayer.cpp
