• Added EXPERIMENTAL timer method to Mojo::Promise.
  
• Added header_exists and header_exists_not methods to Test::Mojo.
  
• Fixed a bug where the finally callback in Mojo::Promise was passed a value, which is incompatible with the
  JavaScript API.
  
• Fixed a bug in Mojo::Promise where the finally method could change promise values.
  
• Fixed a merge bug in Mojo::Parameters where multiple values sharing the same name could get lost.