SideBySide2: Remove Ctrl-F for search in CM3

In vim mode Ctrl-F is "page down" while "/" is search. Remove the
Ctrl-F binding to allow page down to work as expected in vi mode.

Change-Id: Iadd22d3707b70cf51c50a8d8aa1bd1cdbb372258
Cache ChangeKind computations

We want to be able to evaluate copyAllScoresOnTrivialRebase and
copyAllScoresIfNoCodeChange at submit rule evaluation time based on
the current value for each label, not what it happened to be at the
time a new patch set is created. This computation is potentially
expensive, so cache it.

Keys contain the SHA-1 of a patch set, and the merge strategy name,
since the triviality of a rebase may depend on the strategy used.

Since this functionality is not yet implemented, don't persist any
data in memory or on disk yet.

Change-Id: Ica7a7a52ecc317c710bdac3de41bd98c46465b05
Merge "Cache ChangeKind computations"
Merge "SideBySide2: Remove Ctrl-F for search in CM3"