v0.4.0

• New assembly Ketchup.Api.dll can be used to create external devices. Contains two new interfaces IDevice and IDcpu16 which can be used to implement external devices in separate add-ons. No need to reference Tomato assembly for this. Any PartModule on a vessel which implements IDevice will automatically be connected to the CPU. Existing devices: keyboard, clock, and monitor have been reimplemented as separate modules which implement IDevice. As such, each device is now responsible for its own UI.
• CPU and devices will now save and restore state in the persistence files.