Remove Hoe

Tools like Hoe and Jeweler were created back in the days where creating
gems and managing gemspecs were more difficult and a relatively new
thing to do. However, gem management has come a long way now! This patch
cleans up your Gemspec and removes hoe as a dependency. Additionally, it
adds a few nice little version constants so that people using the
library can easily access the version from their code if they want to!

Signed-off-by: David Celis <me@davidcel.is>
Add Gemfile.lock to gitignore

Yehuda put it more clearly than I can, but having Gemfile.lock checked
into a library as opposed to an application enforces a level of
strictness that isn't necessary. With the version specifications for the
gem's dependencies present in the .gemspec, theoretically bundling any
latest patch version of those gems should be fine.

Signed-off-by: David Celis <me@davidcel.is>
Re-organize the README a bit