remove branches from .travis.yml

It is too hard to run travis on forked branches.
It disturbs pull request process.

--HG--
extra : source : 69e6e2b6888530a3ca0dee5fe9d70df796270994
Test cleanup.

--HG--
extra : source : efa3d95a282c16487a567d2b8653dce344feab37
Change tests to use ruby/rails assertions.

--HG--
extra : source : 9fa5da91184bc2b0a619e6cc42eb895a0de77f3c
Test cleanup.

--HG--
extra : source : 6411a4d531372ea6c710c2811292f4be9cfc7dd2
Test cleanup.

--HG--
extra : source : 848cf08704d22c7f7c7a314aac3785f0ed971fc2
Test cleanup.

--HG--
extra : source : 1b995c4f3d6d76fd22755e01b384fb3ce8cad44c
Removed object_daddy dependency.

--HG--
extra : source : e8a50ea4f242942fef7f31112b18a6935476e347
Renamed object_daddy_helper and removed exemplars.

--HG--
rename : test/object_daddy_helpers.rb => test/object_helpers.rb
extra : source : d7706b7176971be01432f9ae646e8f2d3629d3c3