Update Travis CI matrix

Author: sferik

.travis.yml

@@ -5,24 +5,19 @@ env:
     - JRUBY_OPTS="$JRUBY_OPTS --debug"
 rvm:
   - 1.8.7
-  - 1.9.2
   - 1.9.3
   - 2.0.0
   - 2.1.10
-  - 2.2.5
-  - 2.3.1
+  - 2.2.6
+  - 2.3.3
   - jruby-18mode
   - jruby-19mode
-  - jruby-head
-  - rbx-2
+  - jruby-9.1.6.0
   - ruby-head
 matrix:
   allow_failures:
-    - rvm: 1.9.2
     - rvm: jruby-18mode
     - rvm: jruby-19mode
-    - rvm: jruby-head
-    - rvm: rbx-2
     - rvm: ruby-head
   fast_finish: true
 script: bundle exec thor spec