Update docs for configuration and rebuild interval

Changelog for 0.2.1:

Commits
c6467d8 Update table heading by @alexellis
d49094f Add additional config vars by @alexellis
aff926c Add docs for configuration by @alexellis
7973e78 PRint config on start-up by @alexellis
98e1110 Make NATS more verbose by @alexellis

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