Unpoly 3.5.2 released #557

Continuing our focus on stability, this release addresses some long-standing issues:

• Fix a bug where <video> and <audio> elements would render incorrectly in Safari (#432).
• Fix a bug where <script up-keep> elements would re-run during subsequent render passes.
• Fix a bug where <script> elements would not run when targeted directly.
• Fix a bug where <noscript up-keep> elements would not be persisted during fragment updated.
• Fix a bug where <noscript> elements would lose their text content when targeted directly.