When creating the template node for a block, we create htmlelements and
set their (static) attributes. But this can have side effects. For
example, setting the src attribute for an img element will trigger a
request to fetch the image.
We avoid that issue by simply setting the html element template node
inside a <template/> element.
Note that I don't really see how to test this fix in jest: we don't have
a real browser, and no real way to check for this side effect.
closes#1257
This commit makes all errors thrown in owl use a custom error class. The
main point of this is to always wrap user-code errors that happen during
the owl lifecycle so that they can be treated uniformly in onError by
checking the cause property, and also allows user code to differenciate
owl errors from non-owl errors reliably at runtime.
Géry Debongnie