Emittance rounded to 2dp

There are times whereby we only wish to have the emitters glow and not emit light. ie when adding bloom to emitters

The current minimum allowed in the UI is `0.01` which means that a good amount of light is still emitted. While the amount of light is typically not noticeable at more typical Exposure values in cases whereby only emitters are being rendered for the purpose of bloom and a high Exposure value is used it is extremely noticeable.

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Typing a value smaller than `0.01`, pressing enter, and then toggling the `Lighting` tab has the value reset to `0.01`. ie `0.001`, etc.

Entering `0.0001` or lower results in it being rounded to `0.0`.

Regardless of entered value below `0.01`, and what the UI shows (for 0.01>x>0.0001), the rendered results looks the same as `0.01`.