Depend on Ruby >= 2.2.2.

Remove wirble from Gemfile, as dependency-ci objects that it has no license and it's not really neccessary.

Author: gkellogg

.travis.yml

@@ -4,12 +4,10 @@ script: "bundle exec rspec spec"
 env:
   - CI=true
 rvm:
-  - 2.0
-  - 2.1
-  - 2.2.4
-  - 2.3.0
-  - jruby-9.0.4.0
-  - rbx-2
+  - 2.2.5
+  - 2.3.1
+  - jruby-9.1.2.0
+  - rbx
 gemfile:
   - Gemfile
   - Gemfile-pure
@@ -20,4 +18,4 @@ cache: bundler
 sudo: false
 matrix:
   allow_failures:
-    - rvm: rbx-2
+    - rvm: rbx

Gemfile

@@ -21,7 +21,6 @@ group :development do
 end
 
 group :debug do
-  gem "wirble"
   gem "ruby-debug", platforms: :jruby
   gem "byebug",     platform: :mri
 end

README.md

@@ -18,7 +18,7 @@ Install with `gem install rdf-rdfxml`
 
 * 100% free and unencumbered [public domain](http://unlicense.org/) software.
 * Implements a complete parser for [RDF/XML][].
-* Compatible with Ruby >= 2.0.
+* Compatible with Ruby >= 2.2.2.
 
 ## Usage:
 Instantiate a parser and parse source, specifying type and base-URL

rdf-rdfxml.gemspec

@@ -20,7 +20,7 @@ Gem::Specification.new do |gem|
   gem.require_paths         = %w(lib)
   gem.has_rdoc              = false
 
-  gem.required_ruby_version = '>= 2.0'
+  gem.required_ruby_version = '>= 2.2.2'
   gem.requirements          = []
 
   gem.add_runtime_dependency     'rdf',             '~> 2.0'