Internal ability to hold spectrum frame

[automatl]

Could be used for two features:

• When spectrometer release speed set to 'never' hold spectrum even if no signal is passing
• Explicit 'hold' button which will still current frame until disabled.

[naught101]

It would be good to have a peak line, too - you could have the main spectrum fall off fast, and a peak line (maximum of last X seconds) fall off much slower.