Update gems for OSX 10.10 support.

Ran in to issues when trying to set up on OSX 10.10 because of the rubyracer and libv8. Needed to bump them  up because building the v8 gem was failing. 

Then I ran into another issue related to pry and rb-readline. Basically if you used the arrow keys in the console it would throw a unicode error.  This was fixed by updating rb-readline.