Remove async keyword, avoid iooxa undefined issue

[lrq3000]

Awesome work @rowanc1 ! Sorry I couldn't come back to your project before, but now I'm starting again with the new iooxa package you've made :-)

I love the changes so far! I am now trying to do more complex stuff (I also learnt a bit of modern javascript since then :-) ), so here are a few suggestions to improve the doc IMHO:

• Remove the async keyword in the intro to avoid this issue when trying to access iooxa from a custom javascript function. It may be obvious for more experienced JS developers but for me it wasn't :-/ So I'd suggest it's better show an intro example that doesn't risk the user running into this issue. This is what this PR does.

• Add the examples you wrote here in the doc, in a new section "custom javascript functions"? Right now the doc only includes a section for "Runtime" which is great to build new components, but it doesn't explain how to access programmatically already existing components through iooxa.

• How to call custom javascript functions, as previously discussed here (although it seems these examples do not work anymore or at least not on all input types, as the :change attribute cannot call JS functions on r-select for example, didn't yet try others).

[rowanc1]

That is a great idea to remove the async keyword. Thanks for the suggestion. :)

I will take another look through your other comments before merging this in.

[lrq3000]

Thank you so much @rowanc1 ! iooxa's expressivity is astonishing!

BTW I found how to do the last point, how to call custom javascript functions from a r-select, using the onclick method instead of onchange or :change (onchange should work as it does with standard html select, but for some reason this event doesn't work properly on r-select). An example:

<r-select bind="myvar" values="A,B,C,D" onclick="myCustomJSCallback()"></r-select>