Replace teacher with team-leader in the spec.

There's no functional change in this new spec version, just a fix
to use the current SR terminology. Also change "team leader" to be
hyphenated. This removes the previous duplicate terminology for
this role.

Change-Id: Ifa63fc6a720f8ff774cacb3d3f23af2f89884bfc
Expose whether a user is each of the nemesis roles.

This isn't exactly privileged information, and there doesn't seem
to be a good reason that it wasn't available previously, but it is
very useful information to have. It will also make improving the
web UI easier.

Change-Id: I26c12b9066dab11b0a4fd8770cba7eedb13fb721