Renaming gemfile variable to gemspec

For clarification, since the file being altered is a gemspec, the
variable name should reflect that.
Replacing original_name

We already have the original_name from the name variable
Removing duplicated logic
Clean run of namespace renaming
Properly escaping character for gemspec

This was showing up as `NUL` in generated plugins.
Rearranging code, adding README
Reworking how the engine.rb file is created
Adding rspec as a dependency
Rearranging git commands
Updating template, the installation passes
Merge pull request #24 from jeremyf/refactoring

Refactoring - a major restructuring