Move yardoc configuration to .yardopts

Using `.yardopts` allows also external services such as Rubydoc.info
to pick up the correct Yard options.
The NEWS file is not available
Add yard-tomdoc to gemspec dependency
Merge branch 'yardoc' of github.com:gioele/coco into gioele-yardoc

Conflicts:
	Rakefile
Merge branch 'gioele-yardoc' into development
Add tomdoc plugin in .yardopts
Add Changelog file in documentation
Fix some typos in Changelog
Update Gemfile.lock
Update Install section in README
Delete the install task
Merge branch 'gem-rake-task' into development
Add documentation to context.rb
Make CoverageStat a utility module
Use Array.compact instead of custom method
Better naming
Reordering methods
Add documentation
Merge branch 'refactor-coverage-stat' into development
Refactor a bit HtmlDirectory