Update star's interpretation of left/top

To align with all other elements in Shoes 4, the star should use
left/top as the actual left/top, not the center of the element.

See #423 for discussion on it. This is a deviation from Shoes 3, but was
purposefully chosen as the simpler option for consistency going forward.
Sample fixes for change in left/top for star
TextBlocks have #parent not #parent_text, refers to the same though
remove coveralls gem references
Centralize code_coverage running
Throw away extra Gemfiles in shoes-core/shoes-swt

* Development dependencies are already in the top level Gemfile
Method extractions and clarifying comments
Respect center option on star
Merge pull request #993 from shoes/star-left-top

Start now interprets left/top as upper left corner, like all elements

* This derviates from shoes3 behavior but the decision was taken for consistency reasons, you can use the center: true options to get vintage behavior
* Changelog: breaking
Add breaking changelog category
Stop testing against jdk6, 9k doesnt support it either way
Merge pull request #1002 from shoes/remove-coveralls

Remove coveralls and some duplicated files in the gem structure
Merge pull request #1005 from shoes/breaking-changelog

Add breaking changelog category
Merge pull request #1001 from shoes/spans-parent

TextBlocks have #parent not #parent_text 

* fixes #979
* Changelog: improvement
Temporary workaround for travis-ci/travis-ci#3067

* somehow jruby19 went on to use 9k...
Merge branch 'master' into shoes-package for travis fix