Add precompiles to reduce time to first Revise.revise()
Perhaps the most annoying thing about Revise now is that the first
revision is quite slow, about 3.1s on my machine. This PR drops the time
to about 2.4s. Basically the idea is to precompile statements that
Revise will need.
Discovered via the new snoopi_deep/Core.Compiler.Timings framework.
