This reverts to the way stable does things. Smooth seeking is nice and
all, but slows things down and doesn't give the instant reponse that
mappers are used to.
This should fix some performance issues regarding seeking as it no
longer tries to render large portions of the map during the seek
operation.
Note that I've also forced the summary timeline to always non-smooth
seek. It was bugging out in weird ways when doing smooth seeks and I
don't want to attempt to fix it.