add -T option to use margo_forward_timed()

See merge request !15

update to avoid deprected margo fns

Closes #4

See merge request !14

- fixes #4

- must explicitly specify domain now, maps to first IB port

adjust bake benchmark to reflect margo API change

See merge request !13

update benchmarks to reflect api changes in margo json MR

See merge request !12

- take all CPUs available on the allocated nodes

Reflects new packages installed in big July 2020 theta upgrade

interoperability test updates

See merge request !11

Of particular interest to us is the Intel-MPI bugfix (bebop), but let's
see what else breaks.

example programs for margo interoperability

See merge request !9

- to be used for producing new contexts

see https://github.com/spack/spack/issues/15145 for details but 'spac
boostrap' isn't even a no-op any longer as of 0.15

- should not be needed any longer

- file backend checks for this on startup now