Keep live coding live

* Rollback to previous pattern on parse error @jwaldmann
* Increased strictness to catch parse errors earlier @jwaldmann @yaxu
* Support for superdirt 'panic' @yaxu
* Increase hosc upper bounds to admit 0.18
* New function 'splat' @yaxu
* `quantise` now uses round, add qfloor, qceiling variants and qround aliases @lwlsn
* Add ghc 8.8.3 to travis @jwaldmann
* Switch `substruct` to use binary pattern @yaxu