add coveralls to gemfile
setup coveralls for cucumber
setup coveralls for unit tests
enable coveralls on Travis-CI
add status badge to README
simplify conditions for coverage reports
Change links to Liquid documentation
add features to test source and dest matching
Fix handling of source-dest matching being too aggressive

Fixes #1130.
extend feature tests and use scenario outline
Merge pull request #1539 from maul-esel/coveralls

Add support for coveralls.io coverage reports
Update history to reflect merge of #1539
Require 'pathname'
Merge pull request #1556 from maul-esel/dest-match

Fix up matching against source and destination when the two locations are similar.
Update history to reflect merge of #1556
Merge pull request #1553 from penibelst/change-link-liquid

Change links to Liquid documentation
Update history to reflect merge of #1553
Update history to reflect merge of #1255