Don't reassign Runner constant

With the tests in the correct module we don't need to reassign the
constant Runner, and make it look cleaner.
Merge pull request #364 from sideshowcoder/test_cleanup_constant_assignment

Don't reassign Runner constant
FIX 301 search local project root and put .zeus.sock there

- make sure we always put the zeus socket in the project root, when
  launching zeus
- look for the socket in the project root when trying to connect.
- ProjectRoot is defined as the next directory down with a Gemfile
Merge pull request #365 from sideshowcoder/sub_dir_zeus_sock

#301 search local project root and put .zeus.sock there
Make README note about autorun more obvious
Merge pull request #361 from antifuchs/flatten-client-backtraces

Remove recursion in favor of iteration for lower backtrace depth
Easy `make` for linux users

Building this gem in linux can be a little tricky cause the lack of `xbuildtool`, but we can now run `make linux` and all go smoothly.
Obviously, this only compile the binary for the current user's architecture and is meant for personal use only.
Merge pull request #387 from Iazel/patch-1

Easy `make` for linux users
Upgrade fsevents-wrapper so it can build on Xcode5