Add UInt.toBools conversion to Vec[Bool]
Make UIntToOH return type more concrete
Fix CSE bug
Make CSE faster, more scalable

It doesn't use a graph-wide search, but instead a per-module one.
CSE code cleanup
Merge branch 'counter' of https://github.com/ucb-bar/chisel
add trace parameter to tester
revise createClkDomain
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