Add Ruby 2.1.0 to .travis.yml
Use SVG for status badges in README

http://shields.io/ provides many standardized badges for OSS. The PNG versions provided by Shields are similar to the images currently used, but the SVG versions added here are more legible on high pixel density displays.
Update README.md

Gemfile is ruby also.
[ci skip]
remove sinatra from Gemfile
Merge pull request #1179 from simi/patch-1

Update README.md
Merge pull request #1164 from salimane/pr_ruby_2_1_0

Add Ruby 2.1.0 to .travis.yml
remove rubysl-json from gemfile
Merge pull request #1184 from mcfiredrill/rbx-travis-fix

remove rubysl-json from gemfile
Merge pull request #1177 from seanlinsley/patch-1

Use SVG for status badges in README
Merge pull request #1183 from mcfiredrill/remove-sintara-from-gemfile

remove sinatra from Gemfile
won't be needing rack-test as well
Merge pull request #1187 from mcfiredrill/remove-rack-test-from-gemfile

won't be needing rack-test as well