Add `.travis.yml` and `README.md` file

This also bumps the version early to avoid cabal issues, as otherwise the
build on GHC head will most likely fail in the last `cabal install` step
as GHC head is likely to have the last released version already installed.
Declare language extensions locally via `{-# LANGUAGE #-}`s

This recommended practice since Haskell2010.
Modernize `terminfo.cabal` to `cabal-version: >=1.10` format

This makes `terminfo` dependent on a compiler supporting
Haskell2010 (e.g. GHC 7.0.1 or later). Supporting & testing GHC versions
prior to 7.x is rather tedious.
Merge pull request #1 from hvr/enable-travis

Add Travis support & some packaging cleanups