diff => ldiff
updated all rspec-* to 2.13, fixed spec tests for shell_out
diff.rb:87 diff -> ldiff
wrote diff functionality for diff.rb
fixing logic in udiff method, still some errors to review
got ldiff method working, fails two tests specific to shell_out (diff_spec.rb:402,418)
commented out shell_out tests in diff_spec.rb, cleaned up diff.rb code
removed old shell_out tricks from diff.rb, fixed whitespace
removed old shell_out tricks from diff.rb, fixed whitespace
fixed spec tests