Add Version class

Library/Homebrew/version.rb

@@ -0,0 +1,25 @@
+class Version
+  include Comparable
+
+  def initialize val
+    return val if val.is_a? Version or val.nil?
+    @version = val.to_s.strip
+  end
+
+  def nums
+    @version.scan(/\d+/).map { |d| d.to_i }
+  end
+
+  def <=>(other)
+    @version <=> other.version
+  end
+
+  def to_s
+    @version
+  end
+  alias_method :to_str, :to_s
+
+  def self.parse spec
+    Pathname.new(spec.to_s).version
+  end
+end