added image file check for background images
images not found does not raise error
now unfound images do not raise an error
Merge branch 'no-file-error' of github.com:presidentJFK/shoes4 into no-file-error
removed pry
Add #displace, with specs and sample
use def_delegators instead of method_missing for Shoes::URL

* we know all the methods we want to delegate in advance, so
  def_delegators communicates that better
* also it is (presumably) faster than walking down the method
  chain once already
* also it is less prone to errors... e.g. trying to delegate
  methods we do not want to delegate
Make setting the parent of a widget more understandable
Add displace methods to Dimensions
Merge pull request #608 from shoes/replace_method_missing

use def_delegators instead of method_missing for Shoes::URL
Merge with master. Hairy
Merge pull request #613 from shoes/no-file-error

Gracefully handle missing background images
Use #update_position
Change #displace to #update_position in gui
Merge with master
Fix button specs by removing huge margin and provide error margin

* margin was so huge that width/height went negative, probably
  something we should be aware of/fix in the future - will file
  an issue
* provided an error margin of 1 because of... computers and
  floating point numbers
Add some displace specs to dimensions
fix typo in integration, thanks to @wasnotrice ! Wasn't a grean name ;)
Merge pull request #592 from shoes/displace

Add #displace by @wasnotrice :)