Upgrade gems to rails 4

This updates the gems, and rearanges the gemfile, to match the rails4
pattern.
Update configs to rails 4

This updates the config files to match the rails 4 specifics.
Update demoapp controller to strong parameters

This updates the demoapp's controller to use strong parameters.
Use rspec by default

This patch sets the default rake task to rspec.
Use asset pipeline for image resources

Image resources loaded via css should use the asset pipeline. This
patch renames the jquery.modal.css to .scss, and uses the `asset-url`
method to reference image resources.
Bump version

Bumping the version to 1.0.0. According to Semver, when making
backwards-incompatible changes, the major version should be bumped.
Since the rails 4 upgrades, this has become incompatible with prior
versions of rails.