dev: allow commandline GHCRTS args in Makefile
dev: allow for variable verbosity level
dev: refactor: split 'make build' into stages
bugfix: https://github.com/haskell/cabal/issues/657

use -rm to
[[http://stackoverflow.com/questions/2989465/rm-rf-versus-rm-rf][ignore
errors during make]]
travis: reduce verbosity for dependencies
travis: install custom version of hsenv

have a travis/ folder to track any such custom external dependencies