Relax bundler version
rspec-mocks/master depend on rspec-support/master

/Users/sane/.anyenv/envs/rbenv/versions/2.1.0/bin/ruby -S rspec
./spec/tachikoma/application_spec.rb ./spec/tachikoma/settings_spec.rb
./spec/tasks/app_task_spec.rb -cfd --backtrace
/Users/sane/.anyenv/envs/rbenv/versions/2.1.0/lib/ruby/gems/2.1.0/bundler/gems/rspec-mocks-8ec4f5b26c80/lib/rspec/mocks/argument_list_matcher.rb:2:in
`require': cannot load such file -- rspec/support/fuzzy_matcher
(LoadError)
Merge pull request #82 from sanemat/feature/relax-bundler

Add bundler upper limit, use rspec-support/master