pkgwat: further package adjustments

- Remove Gemfile and Rakefile in %prep
- Delete extraneous boilerplate comment about C extensions
- Move README.md to main package
- Exclude test suite and Rakefile from binary packages

Delete the unused debugger patch from Git.

Adjust the Summary to be grammatically correct and to avoid using the package name in the summary text. Adjust the Description to avoid talking about ideas for future features.

Remove the dependency on thor, since that was not actually a valid requirement for the pkgwat gem.