Dalbeattie

• Minor change to _splice so that it respects if the speed parameter was already declared @onthepeakofnormal
• Some tests for chords @cleary
• Remove direct semigroups dependency @yaxu
• Derive functor for pattern @yaxu
• Handle negative ratio shorthands for rationals @ndr_brt
• drawLine - draw non-events with periods @yaxu
• Parse chord without root note @yaxu
• Fix clock sharing between tidal processes @yaxu