Revert "User's guide (README)"

This reverts commit 03368c02fb97b9fa35abafbbfbbc8be5056f2c53.
Revert "Default help page"

This reverts commit b2d83b2f0c7d5ef84e6eb3bb59e6692b790c93ef.
Revert "Default front page"

This reverts commit a50d340e36fcb98db5a92633adc85561d5071242.
Add CHANGELOG.md and README.md.

The extra-doc-files property requires cabal-version >= 1.18 (c.f.
http://coldwa.st/e/blog/2013-08-21-Cabal-1-18.html).  Bump this requirement
from 1.10.
Add homepage and bug-tracker to cabal file, linking to github.
Update tested-with version: GHC-7.8.3.
Bump version to 0.2.0.3 from 0.2.0.2.