Move idiomorph/htmx.js to something like htmx-ext-idiomorph?

[botandrose]

It seems to me that the dependency arrow is backwards on this one. Idiomorph is composed by HTMX, not vice-versa. Or, put another way, HTMX knows about Idiomorph, not vice-versa.

@1cg What do you think?

[botandrose]

Could probably also resolve #38

[botandrose]

Probably going to happen eventually, we'll keep it in for now.