* convert important functions to methods
* rename EscXXX to XXX in NodeEscState
* rename local variables more friendly
* simplify redundant code
* update comments

Change-Id: I8442bf4f8dde84523d9a2ad3d04b1cd326bd4719
Reviewed-on: https://go-review.googlesource.com/30893
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>