Remove red-green gem

It doesn't appear to work with MiniTest
Helpers no longer include type attribute

Jammit uses Rails tags_with_options for css tags,
which no longer not includes the `type="text/css"` attribute
Test optional gems against their latest versions
Use double quotes for tag attributes

This way it matches Rails
Convert tests to use MiniTest
"expected" argument comes first on assert_equal

Also convert a few instances of just assert foo==bar to use
assert_equal so a better error message is generated
Test jammit controller under Rails 4
Supply "importer" argument for CssParser >= 3.4

When Sass implemented source map support in version 3.4,
the signature of Sass::SCSS::CssParser.new changed to require
3 arguments
Add url_options method to Jammit controller test

Since Rails has not been "booted", it doesn't setup the "url_for" method
which is called internally by the default url_options method.

Over-ridding it with a blank definition allows the controller's methods
to be tested