What information should be stored in the header?

[eriksjolund]

Information we want to store can either be placed inside the header or as a byte range
outside of the header.
This is sort of an open question: What information should be stored inside the header?
The choice of what to put inside the header will influence the number of bytes read and the number of read operations that it will take for retrieving some information out of the file.

Right now the gene names and the spot coordinate information are stored outside the header but maybe we should put them inside the header?
Advantage: The osd-spot-viewer
(https://github.com/eriksjolund/osd-spot-viewer/blob/master/from_layout/index.html)
would make fewer read calls. The parsing code would be also be somewhat simpler.

Drawback: The header would get bigger. There might be times when that information is not needed
and someone retrieving other information out of the file would have to pay an extra cost.