Merge branch 'release/2.6.0' into develop

* release/2.6.0:
  * Bootstrap v3.0.3 * Respond.js 1.4.1 * Submodules locked to tags instead of master branch
Updated gems
Improved test helper
Support for ruby 2.1
Respond.js 1.4.2
* [dev] Removed active_record from dummy test application
* [dev] Removed debugger and sqlite dependency
* Updated README
* Updated CONTRIBUTING guidelines
* Added .editorconfig
[ci skip]
Do not check Gemfile.lock
[ci skip]
I mean... remove Gemfile.lock!
[ci skip]
Merge branch 'release/2.7.0'

* release/2.7.0:
  I mean... remove Gemfile.lock! [ci skip]
  Do not check Gemfile.lock [ci skip]
  * Updated README * Updated CONTRIBUTING guidelines * Added .editorconfig [ci skip]
  * [dev] Removed active_record from dummy test application * [dev] Removed debugger and sqlite dependency
  Respond.js 1.4.2
  Support for ruby 2.1
  Updated gems Improved test helper