Create a sequencer function in LFE

[oubiwann]

Tasks:

• [x] sequence constructor function parameters
  • [x] sequencer name
  • [x] beats per measure
  • [x] note dudration
  • [x] note sequence + paired volumes
• [x] sequence mutator functions
  • [x] update beats / measure
  • [x] update note duration
  • [x] update note sequence + volumes

Additionally, provide support for "knob twisting" while sequences are playing (via MIDI cc):

• [x] add more control codes for the Arturia modular V plugin
• [x] add cc, cc-on, and cc-off support to xt.midi
• [x] implement linear ramping for cc's

[oubiwann]

Done.