Add example using auto to README.markdown.

Computing the derivative of a function that has a constant parameter
seems a likely use case. When I attempted to do so it took me some
time, though, to figure out that I needed to use auto; in order to
save future users that trouble, it seems logical to add an example to
the README.
HLint clean, removed unused dependencies, updated build system so doctests build with exact dependencies, updated IRC notification, fast apt-get based travis config
Added missing parts of travis config
removed trailing whitespace
Merge pull request #13 from christopherdavidwhite/master

Small addition to documentation
Edited style to match surrounding code for pull request #13
CHANGELOG entry
fixed haddock error
minor version bump
Consolidated travis config. Added -flib-Werror flag
extra-source-files