Update build matrix

- No special case for RSpec 2.99. We'll continue to support (2.x, <  2.99) and 3.
- Ruby 1.9.3 has been EOL'd. We'll no longer support it
- Ruby 2.2.0 should be supported
- Ruby 2.1 has been updated to the latest release in the 2.1 series

.travis.yml

@@ -1,11 +1,10 @@
 language: ruby
 rvm:
-  - 1.9.3
   - 2.0.0
-  - 2.1.0
+  - 2.1.5
+  - 2.2.0
   - jruby-19mode
   - rbx-2
 env:
   - RSPEC_VERSION="<2.99"
-  - RSPEC_VERSION="~>2.99"
   - RSPEC_VERSION="~>3.0