Consider renaming the crate

[cmnrd]

Currently the repository name is reactor-rs and the crate name is reactor-rt (rt for runtime). I think this is pretty confusing and we should consider renaming the crate. As @oowekyala pointed out in #5 naming the crate reactor-rs does not make much sense either due to the redundant rs. Probably just reactor would be a more suitable crate name. This would be in analogy to the reactor namespace in reactor-cpp.

[lhstrh]

If the name is available, reactor sounds fine to me.

[jhaye]

If we want to publish to crates.io at some point in the future, then reactor is already taken. reactor-rs for the repo is fine, but for the crate would be confusing, because the -rs suffix is commonly used for C wrapper libraries like bzip2-rs.

I would say it's best to either keep reactor-rt or to spell RT out to reactor-runtime.