Linear support and important bug fix (0.3.0)

This is a backwards-compatible release with the following changes:

• Added support for “linear” feature control, which means Plug₂in supports better strokers and fucking machines now!
  (Please do take care when adding support for them, as they physically behave very differently from other features and are usually stronger!)

  Thanks to Kredyn for making this possible!

This release should also fix two bugs I found while implementing the above:

• Oscillating devices without vibration features should now stop correctly and should also briefly activate when connecting now.

• The alphabetic pattern scheduling system likely didn’t work correctly in earlier releases.
  The individual task delays should be correct now, rather than being delayed to the last timestamp in the pattern.