cache the context runner
cache the context runner

git-svn-id: f1a1267e29db6ed751edc5bdb54cf7d87c16124a@509 410327ef-2207-0410-a325-f78bbcb22a5a

die-antwort/rspec-tmbundle,phinze/rspec,graaff/rspec,patmaddox/rspec,chip/rspec-tmbundle,alitalia/rspec,infininight/rspec-tmbundle,rspec/rspec.tmbundle,dchelimsky/rspec,die-antwort/rspec-tmbundle,patmaddox/rspec2rails2,rspec/rspec.tmbundle,alitalia/rspec,weplay/rspec-rails,dchelimsky/rspec,dchelimsky/rspec-stories,drnic/rspec-rails,mcmire/rspec-rails,dchelimsky/rspec-stories,patmaddox/rspec,infininight/rspec-tmbundle,mrkn/rspec,dchelimsky/rspec-rails