No-JS mode refactoring

Now JS is controlled with a make variable as opposed to a proproc define.

This allows skipping compiling a whole bunch of files when JS is
disabled, e.g. whole freezing step on ESP, or compiling v7.c on CC3200
which takes a while only to be discarded in its entirety later.

Var name is SJ_ENABLE_JS (note change from disable logic to enable to be in line with other stuff). Default is 1, meaning JS is enabled.

Also changed clubby knob in the same way: SJ_ENABLE_CLUBBY, default is 1 as well.

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