Start decoupling front end and back end.

Instrumentation code doesn't work with editors directly anymore.
Decouple some more.

Now, editors are only used in tool.rkt and display.rkt.
Add a quick and dirty command-line mode.

Why didn't I do this earlier.
Refactoring.
Allow relative path from the command-line.
Add a flag for verbose mode on the command line.
Do locality merging in command-line mode.
Fix comment.
Implement cross-pass locality merging.

Merge sequence specialization reports between `for' and TR.
Push locality merging into the back end.
Separate internal processing IR from display IR.
Suggest the right kind of sequence specialization.
Fix info.rkt for 5.3.6.
Implement locality merging for double sequence specialization failures.