Prefer Dir.mktmpdir over manual tmp dir in tests
Fix Utilities#os. Should be module-level method
Prefer Pathname#new over File.expand_path for performance
Put stdlib requires in the same place
Reorganize the spec_helper.rb
Fix gem dependencies installed by Travis
Move Utilities#get_repository into Repository#find

In an effort to start moving all repository details moved
into their own respective classes and objects for a better
design model and testing, move the repository reference into
a thread-safe object for later re-use.
Small refactoring to simplify
Rename Repostory to Repo for brevity
Merge master changes

Conflicts:
	lib/git_statistics/collector.rb