add DV SP / DV LP icons

[dericed]

From the abst value in the csv, deduce the difference between abst in frame n and frame n-1. Let's call that ABST_DIFF. I'd like an icon shown on the capture interface depending on the value of ABST_DIFF.

If ABST_DIFF = 5 (+/- 0.5), then show DVCPRO-lamp-lit.svg
If ABST_DIFF = 6.66 (+/- 0.5), then show DV-LP-lamp-lit.svg
If ABST_DIFF = 10 (+/- 0.5), then show DV-SP-lamp-lit.svg
If ABST_DIFF = 15 (+/- 0.5), then show DVCAM-lamp-lit.svg
else show nothing

Can we also reuse the same timer used for the frame-speed value in #830, so that the icon should only show if the ABST_DIFF value is very recent.

The icon can be placed to the left of the deck controls.

[libbyhopfauf]

@dericed sounds good to me! I also added in my research about detecting DVCAM and DVCPRO to #552 :)

[dericed]

@libbyhopfauf, thx i updated the original comment