UI/API changes
- CHANGE: Add IPv4/6 toggle to DNS measurement definition in measurement form
- CHANGE: measurement form improved estimate (more precise)
- CHANGE: measurement form changes for traceroute (hide ext header size options if not v6)
- FIX: partial fix for favourite probes not showing (still need to deal with API caching issue)
- FIX: layout issues when toggling menu open/close
- FIX: anchors on coverage page, scrolling
- FIX: formatting of cols for probes/msm listings
- TWEAK: clarify UTC meaning in measurement form timepicker