Font families are now cached. There probably should be a mechanism to
refresh the cache, but we don't currently have a "signal" to notify us
when a font is installed. Presumably, this could be something that
fontdb would eventually add, rather than us building our own.
Closes#48
- Caching font family resolution to avoid scanning the database over and
over. The db should still be cached, but this makes repeated setting
free.
- into_switcher rename for Dynamic<WidgetInstance> to avoid conflicting
with Switchable::switcher()
- Dynamic debugging is less verbose
- IntoDynamic<Validation> for Result<T,E>
- Input no longer blinks cursor when disabled.
