Initial generalization and polish.
Generic Vector input.
Lots of SPECIALIZE to retain speed.
Specialize to Unboxed and Storable vectors.

The vector type is carried from input to output, and specialized for
Unboxed and Storable.
Code simplification; address all hlint warnings.
Added a test suite.
Added travis-ci integration.
Removed unused dependency.
Relaxed base dependency.
Added a README.
Fixed a haddock styling issue.
Improved package description.