v0.9.3-pre

• Simulating a model no longer fails on the diagram beside it. Starting a simulation also
  refreshes the diagram, and when no open diagram matched the model the refresh threw
  NullPointerException ... KGraphDiagramServer.getSourceUri(), which surfaced as "An error
  occurred during simulation start" on a model that compiles and simulates perfectly well. The
  diagram is now found under either spelling of its URI -- diagrams are keyed by the client's,
  which percent-encodes a path with spaces, while the simulation carries the decoded one -- a model
  with no diagram open simply skips the refresh, and a refresh that fails can no longer take down
  the start, step or stop that triggered it. Closing a preview now also drops its view context
  under either spelling instead of leaving a stale one behind.
• The language server is ended when the window closes or the server is restarted. The client
  only asked the server to exit, so one that was busy compiling or simulating outlived the window
  and kept its whole JVM heap until the machine was rebooted, once more for every restart. The
  server is now ended for good, together with the compilers and simulations it started, and a
  restart whose shutdown timed out kills the old server and starts again instead of leaving a dead
  client behind.
• A hanging compiler probe no longer freezes the window. Looking for gcc runs before every
  build; which and xcode-select now give up after five seconds so a dead network mount cannot
  block the extension host.