Move communication stuff out of main

Split tasks into separate methods and run each one of them in a separate
goroutine.
Pool txns according to input tx curve
use a tempdir for chainserver datadir
IMPORT PATH MODIFICATION CHANGESET
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Please use this changeset as the first one on top of the conformal codebase.
Note that if there are new imports, they need to be changed as part of this
changeset. In general, use "git rebase" on github.com/conformal's version
and apply this changeset first.