[#53] Added handling for GitHub's ping event.
Merge pull request #55 from inaka/jfacorro.53.handle.github.ping.event

[#53] Added handling for GitHub's ping event
[#56] Create comments with relative diff position.
[#56] Added test.
[#56] Improved test. Fixed bug.
[Closes #56] Used re:run/3 options.
Merge pull request #57 from inaka/jfacorro.56.relative.comment.position

[#56] Relative position for PR comments
[Closes #59] Using API to get files' content.
Merge pull request #60 from inaka/jfacorro.59.file.contents.using.api

[Closes #59] Using API to get files' content
[#24] Improved elvis rule application runtime by a half through the caching of source and parse tree data.
[#24] Executable path length rule. Test failing.
[#24] Reimplemented rule. Tests passing.
[#24] Improved implementation. match nodes are being counted wrong.
[#24] Merged.