Remove '--track' from magit-branch-popup-defaults
Use prefix in name of all custom maps
Add file-map prefix command

This prefix will be used for find-file functions that don't already have
a shorter keybinding.

This commit adds two functions to the map, `view-file' and
`magit-find-file', which both have an other-window analog in
`ctl-x-4-map'.

View mode can be accessed using ',v' right after finding a file, so the
`view-file' binding might not be too useful.

`magit-find-file' was in my magit-specific map, but it makes sense to
have it here because it's useful in buffers outside the magit status
buffer.
Add snippet for h5py import
Fix ctl-x-4-map binding

I was unbinding "R" and then binding it again later because I didn't
realize that it wasn't a default.
Move dired-copy-project-filename-as-kill

This is more consistent with location of
'km/org-open-dired-marked-files'.
Break up km/dired-copy-project-filename-as-kill

Plan to use `km/dired-copy-filename-relative-to-directory' elsewhere.
Add km/dired-copy-relative-filename-as-kill
Make prefix map for dired-copy-filename functions