Fix bug with test req_query

`test` requires quotes around variables with =, or it can fail when
the variable is missing (a list of 0). In this case it would with an
ugly error message.

I'm not 100% sure that this change is necessary - req_query should in
theory always contain one item - but there's no harm in adding the
double quotes.
Fix error on macOS

On Linux, `file` uses the `-i` option for mime types, but on macOS
that option is called `-I`. The long `--mime` option is cross-platform.
Support running `main.fish` from a different dir
Allow using other shells in %%%

Thanks Tim Clifford for the patch!
Fix validation for leading and trailing slashes in URL
Fix normalisation of dot paths
Update documentation
Support Spartan and Mercury protocols
Support and prefer ncat
Add req_query variable
Add paragraph count to gemlog intro
Fix mime meta line
Normalise path to remove /./
Add some of my functions to the default includes
Allow showing source and true multiline eval
Explain and improve certificate generation
Freeze personal and serve in gitignore
Add directory index preference
First version