Thanks for the suggestion! In the mean time, to install this or most custom Octave packages, you can do the following steps.

1) Download the archive file for your package; for example, bim-1.1.5.tar.gz.
2) Upload the file to your Octave Online workspace.
3) Run the command `pkg install bim-1.1.5.tar.gz` followed by `pkg load bim`. This will install the package for your account without affecting other peoples' accounts.
4) In future sessions, run simply `pkg load bim` to load the package.

If you need to install any of the other dependencies, you can do so using the same steps.