Define rake rule to compile coffeescript

Start making more reliable build system by defining rake rule to rebuild
coffeescript directly rather than using guard.
Add rake rules to build SASS files

Define rake rules to directly build SASS files into CSS rather than
relying on Guard to do so.
Use method to rebuild pages branch

Define a method to rebuild the gh-pages branch rather than doing that
directly in the task.  This will work better with folding.
Update dependency for pages task

Modify the pages task to depend on the compiled files rather than just a
task that runs guard.
Use rake to build index.html

Directly build index.html with rake rather than relying on guard.
Modify Guardfile to use rake

Now that I have rake tasks to do all of the building, modify the
Guardfile to just run rake avoiding duplication of code.
Add Gemfile
Do ERB evaluation in rake process

To allow passing data from the Rakefile to the eruby template, do the
evaluation within rake rather than calling separate erb process.
Create dev.html with different cache busing method

Generate separate index.html and dev.html files, the former should
include hash as part of the path name to allow better caching, the
latter should use query data to make managing the working tree simpler.