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
Reword the "linux" make target slightly

* Ensure that linux_v is always set, no matter what uname says.
* Use the $(shell) make function
* Remove quotes - they seem to not get interpolated for some reason.
* Use mkdir -p to make building work when the gem already has a "man"
  dir.

This fixes #406.
Merge pull request #405 from antifuchs/bump-fsevents-to-xcode5

Fix fsevents-wrapper settings so it builds on Xcode5
Fix "slave `boot` was killed", shorten backtraces

Extract command running from the `go` method. This ensures that the
process running the command never tries to re-register with the client
monitor on the Zeus side, which was what caused the "slave `boot` was
killed" messages mentioned in #410. This was originally broken by the
recursion elimination in #361 (turns out unrolling recursion is hard!).

As a pleasant side effect, this change also eliminates two more lines in
the `go` method from backtraces on commands.
Merge pull request #1 from burke/master

merge