Misc spec clarifications

[constantinpape]

There are a few clarifications that could improve the spec (without changing any content). This could be done for a version 0.4.1 or just rolled into 0.5.

• Specify json encoding Specify the encoding of the json metadata #81
• Constrain dtypes & shape for multiscale arrays: Constrain dtypes & shape for multiscale arrays #2
• Clarify purpose of multiple multiscales Multiscales questions #17
• Clarify json terminology json terminology #66
• Text vs. markdown quotes: The specification uses text quotes and markdown quotes interchangably #38
• Single version information at top level, see just one top-level version #83. (That would be a change of the metadata, but only superficial)
• '.' as separator disallowed before 0.5: Allow . as the dimension separator #135
• whether or not multiple images are supported before 0.5: bioformats2raw.layout #112
• interpretation of the multiscales in a single image group

[joshmoore]

Would you consider #22 ("Update label properties to include example: prefix") under this banner as well? Or does that count as a spec change since we would basically be saying "this isn't core"?

cc: @sbesson

[constantinpape]

Would you consider #22 ("Update label properties to include example: prefix") under this banner as well? Or does that count as a spec change since we would basically be saying "this isn't core"?

cc: @sbesson

I don't have enough background on this and don't understand these parts of the spec (yet). So up to your judgement ;).

[constantinpape]

We should also include #105 here.