Update README.md

[martinamorris]

Added a more user friendly description of package utility, and links to the tergm workshop, 4.0 crosswalk vignette and citation. This updates the README to the new format.

[krivit]

OK, we need to figure out what to do with this. Basically, right now all README files for packages I maintain are generated with the script https://github.com/statnet/utilities/blob/master/mk_README , which uses a template into which package name and other information are inserted.

If we want other text in there, we need to have the script be able to either recognise that the README has been edited manually and merge the changes or be able to incorporate additional information, say from another file.

[mbojan]

Oh... I did not know that READMEs are generated. That will also overwrite the CoC-related paragraph I added lately... Is this a bridge too far in terms of automation? Incidentally, I have no access to statnet/utilities (I'm getting 404).

[krivit]

Oh... I did not know that READMEs are generated. That will also overwrite the CoC-related paragraph I added lately... Is this a bridge too far in terms of automation? Incidentally, I have no access to statnet/utilities (I'm getting 404).

Oops. Added. Yes, that would be clobbered as well. If we are implementing a CoC everywhere, we can add it to the template, so that's straightforward.

It shouldn't be hard to have an "API" for inserting bits of text or perhaps some kind of fences that could be used to extract text to be preserved when overwriting, either.