Get travis passing on jruby 1.8 and 1.9

Had to use open() instead of IO.read so that I could pass
the binary flag.

.travis.yml

@@ -2,7 +2,8 @@ rvm:
  - 1.8.7
  - 1.9.2
  - 1.9.3
- - jruby
+ - jruby-18mode
+ - jruby-19mode
  - rbx
  - ree
 script: "bundle exec rake test features"

features/step_definitions/command_line_steps.rb

@@ -256,7 +256,7 @@
 
 Then /^the image ([^ ]+) has a size of (\d+)x(\d+)$/ do |file, width, height| 
  # see http:https://snippets.dzone.com/posts/show/805
- IO.read(file)[0x10..0x18].unpack('NN').should == [width.to_i, height.to_i]
+ open(file, "rb").read[0x10..0x18].unpack('NN').should == [width.to_i, height.to_i]
 end
 
 Then /^I should see the following lines of output:$/ do |table|

test/integrations/sprites_test.rb

@@ -34,7 +34,7 @@ def map_files(glob)
  end
 
  def image_size(file)
- IO.read(map_location(file))[0x10..0x18].unpack('NN')
+ open(map_location(file), "rb").read[0x10..0x18].unpack('NN')
  end
 
  def image_md5(file)