Ensure interior empty list items and some nbsp are not stripped away

[christhekeele]

The first commit here adds a Gemfile and rspec to the gemspec for easier development, and reworks the test suite with some custom rspec helpers to remove boilerplate, and makes use of the indentation-aware <<~HEREDOC to add some consistency.

It meaningfully changes neither library code nor spec code.

The second commit contains specs written when trying to repro and debug small errors observed by customers during editing experiences with TinyMCE, hence the name tinymce_examples_spec.

• interior empty <li>s are no longer stripped
• certain   are no longer stripped away
• adds some tests for extra percents in output from span quicktags fixed by jeremy previously
• adds some tests for probing around issues with whitespace in tables

[k1w1]

Is this markup correct? When I put that markup into JIRA it is not formatted, I still see the * and _.

[christhekeele]

It looks like the correct way to do this is test{_}test{*}test*_.

[k1w1]

This also does not give the result I expect in JIRA. I see the * instead of the text being bold.

[christhekeele]

The only way I can get this formulation (generated by tinymce when applying formatting to highlighted text or nested formats across words, IIRC) to work in JIRA is something like: *test {*}test. TinyMCE does give us the nbsp in these contexts but we throw it away for a normal space.

Alternatives like shifting the padding spaces outside the tags would force an extra auto-update loop between JIRA and Aha! to normalize.