While this was a workaround for a docs.rs issue (Px/Lp are not
linked), I decided having the shorter import path would look better in
the examples.
It probably wasn't necessary to update all of the references in the
internal code, but I decided it was worth the consistency.
- Blur no longer expands the shadow geometry, but instead is clamped to
avoid overlapping drawing calls.
- Overlay now handles hit tests correctly with regards to the original
relative widget.
- Align was using an Into conversion that wasn't actually correct,
causing the contents to not actually get aligned in some situations.
