Use sane names in Enum class

Get rid of all references to the word “value”. EnumValue’s are just
called enums now. “value” objects when referring to an integer number
are just now called tags. It’s not semantically correct, but there
isn’t a semantically correct name and “tag” is short. Replace “by” in
method names with “for” cause it reads nicer.
Add Deprecator module and deprecate several existing enum class methods

Deprecator module simply prints a warning when the old method is called
and then calls the new method, passing arguments if it’s expecting them.
Add unreleased section to top of CHANGES.md with info on Enum changes