Merge pull request #15 from ShreyasPatil/master

Updated Image comparision code
added test cases to test image comparing steps
added negative test case for image comparing steps
Merge pull request #16 from ShreyasPatil/master

Updated methods and other ruby files
updated test page with new png and jpg image
added negative test cases to test image comparing steps in assertion_steps.rb
parsed ruby files with robocop
readme file updated with website url
updated canned_steps.md with index
deleted assertion steps.rb file
updated image comparing example