bootstrap.sh: document curl TODO
Merge pull request #1676 from tuncer/curl-todo

bootstrap.sh: document curl TODO
Fix a warning.
Enable TemplateHaskell/dynamic on Travis for GHC >= 7.8.
Enable building cabal-install on the Travis build bot.
Travis: check that the cabal-install tarball can be installed.
Travis: unbreak the build.

Hopefully.