First draft
Remove old files
Fix reporter indent
Update README
Update README
Update README
Update README
Revamp runner and add backtrace filtering

* For the first time all gurke feature are passing using
  gurke itself.
Add travis config
Adjust gemspec and version for travis releasing
Adjust rbx version for travis
Fix wording in scenario
Expand hook support and requirement of support files.

* Disable unsupported capybara helpers until we support metadata
Adjust require option
Start in keyword specific step definitions
Add feature and scenario filtering by tags

Add new --tags CLI option to specify how to filter feature and scenarios
to be executed. Several tags can be given as a comma-separated list and
will be ANDed. Multiple occurrences of the CLI arguments will be ORed.

Examples:
  gurke --tags a,b # Will include only features and scenarios tagged
                     with @a AND @b
  gurke --tags a,~b --tags c
    # Will only include features and scenarios tagged with (@a AND NOT
    # @b) OR (@c).

The default for --tags is ~wip.
Improve reporter

* The reporter now prints a step before running it and will colorize it
  according to its status when it's done.
Renaming and code style

* Rename filter variables to better match their content
* Fix some code style issues with spaces in blocks (rubocop)
Fix bug from last commit
Recolorize reporter