Saving calibration / array properties

[nanthony21]

On the issue of providing a built in way to store calibration coefficients.

@nanthony21:
I think this should be in the system config file. Aside from calibration data it would also be nice to have a way to specify default property values. This is currently done via the "System-Startup" config group which works well but seems kind of hacky.
If properties were extended to support arrays then calibration data could easily just be a standard property of a device adapter.

@henrypinkard:
Extending properties to support arrays would be really useful in many ways. What would be the challenges to implementing this?