New UI release (Wonder Woman, Xavier)

• Lots of internal changes about scalability and testability
• Added total_uptime field to API
• Fixed a bug where in rare case the scheduler did not start a measurement
• Fixed some inconsistencies regarding the example API call section in the measurement form
• Users logins now preserve the full URI of the current page so that (for example) upon return the user is taken to the same tab as before
• Fixed an issue where one-off measurements initiated in the UI form were rejected
• Several changes needed because of anchor lifecycle replacements
• Expose first_connected and total_uptime values to the probe archive API