Rails4 fixes

Building on work done by @PragTob and @ferrisoxide, here are the changes that I'm using to get Surveyor to work with Rails4.  Rspec runs with only one failure on my machine (but that failure is also on NUBIC/rails4), and I've cleaned up all of the deprecation warnings and fixed a bunch of stuff that shows up at run-time.

Several months ago I tried to build the NUBIC rails4 branch but I couldn't get it to run the tests cleanly so I based my work on @ferrisoxide's.  I have since (March 2014) merged NUBIC/rails4, although this currently causes one spec to fail.

Thanks for surveyor, it's a useful gem!