Htbulma

* all inputs keep the instance of the callback/caller given on 'onchange=...'
(use the Caller.prior from htag>=0.1.8 to do the trick)

* all inputs can now call a real htag callback (with async/generator etc ..)
* (use htag 0.1.6 with multi bindings)
* SelectButtons & TabsHeader doesn't provide .onchange anymore ! use onchange attribut only !
* in general : the .onchange() was a bad idea and will be removed for others inputs too, soon

* inputs : onchange is now in the signature of constructor of all inputs (prefer this) (like in the past)
* nav : don't show the burger if no entries

* FIX : Fields produced a full static form fields ;-(

* select(name) was bugued ;-(

* Form implements its own submit() method
* Fields, simple object to build a "form" template (can't be simpler)
* bye bye : InputText,TextArea,Checkbox,Slider,RadioButtons,SelectButtons,Select
* welcome : Input,Range,Checkbox,Radio,SelectButtons,TabsHeader,Select,Textarea
* theses new ones are better, in all way (they.work in same way, with .onchange(), name=xxx, and attrs _readonly, _required, _disabled, ...)
* Input can handle a datalist (dict or list) (like a combobox)
* others can handle a dict or list too (radio, select, ...)