Source line tracking added.

Added a an attribute to store the original source code line number
for some elements.
Row class added

Created a class for rows in example tables.
Pattern clearing added

Step patterns that have been loaded into the World can now be cleared.
Typo fix

Fixed a minor typo in a feature file.
Version bump

Gem version bumped for v1.1.0 release.
History update

Updating gem history in preparation for v1.1.0 release.
Merge branch 'dev'