cloneless xontent capturing, sibling-stepping injection
using primitive value, input{Checked,Selected} use DOM property
uric and deuric factory methods fix
jquery-less injectToXxx: calls
{loop,guard}Contents => {loop,guard}Xon
loop{Proc,Xon} => loop{Proc,Xon}Z

The "Z" in the naming is to remind it puts the resulting element
_after_ itself, not _inside_ as guard{Proc,Xon} without "Z" do.
Inspired by Prolog's asserta/assertz.

I plan to add guard{Proc,Xon}Z as well, sometimes.
bump version to 0.1.8