Bump yajl-ruby to 1.1.0

In release 1.1.0, a change was made to use `static void` rather than
`inline void`
(https://github.com/brianmario/yajl-ruby/commit/d9c054514e04120ecd388488d0302e7e2edd3192).
This solves a common bug when using yajl on OSX Lion and above:

dyld: Symbol not found: _yajl_set_static_value
  Referenced from: ~/.rvm/gems/ruby-1.9.3-p0/gems/yajl-ruby-1.0.0/lib/yajl/yajl.bundle
  Expected in: flat namespace
Merge pull request #20 from greggroth/bump-yajl-version

Bump yajl-ruby to 1.1.0