added ability to scale background image, taken directly from augusto
Added initial version of dashed and dotted cell borders.
Fixed syntax error.
Fixed typos.
Fixed single value not working.
Fixed problems with array length when checking border lines.
Fixes for dotted border.
Added page to manual showing how to use border lines.
Added specs for cell border lines.
Add TravisCI badge
Don't parse AFM font files over and over again
Tame wild memory allocation of Prawn::Images::PNG
Require utilities.rb
Tweaked PNG spec to pass under JRuby
remove rbx 1.9 from travisci for now

* there's many failing specs and we're short on time
jruby 1.9 needs the test-unit gem as well
Update manual/graphics/graphics.rb

extra word removed.
A little rewording.
Period removed for consistency.
Merge pull request #405 from koriroys/patch-1

Update manual/graphics/graphics.rb
Soft masks

Soft masks are used for arbitrary transparency. It's like alpha channel in PNG.
Soft Mask is a feature of PDF 1.4