fix deprecation warnings about #find(:first)

DEPRECATION WARNING: Calling #find(:first) is deprecated. Please call #first directly instead. You have also used finder options. These are also deprecated. Please build a scope instead of using finder options. (called from block (2 levels) in <top (required)> at /Users/tcabot/Code/surveyor/features/step_definitions/parser_steps.rb:85)
fix deprecation warnings about the :value option

DEPRECATION WARNING: The :value option is deprecated in favour of `:input_html => { :value => '...'}` and will be removed in the next version. (called from block (2 levels) in ___sers_tcabot__ode_surveyor_app_views_partials__question_html_haml__1185397536205946121_70301830176800 at /Users/tcabot/Code/surveyor/app/views/partials/_question.html.haml:15)
fix deprecation warnings about find_all_by_ dynamic finder

DEPRECATION WARNING: This dynamic method is deprecated. Please use e.g. Post.where(...).all instead. (called from block in <top (required)> at /Users/tcabot/Code/surveyor/features/step_definitions/parser_steps.rb:136)
fix deprecation warnings about Hash#diff

DEPRECATION WARNING: Hash#diff is no longer used inside of Rails, and is being deprecated with no replacement. If you're using it to compare hashes for the purpose of testing, please use MiniTest's assert_equal instead. (called from unparse at /Users/tcabot/Code/surveyor/lib/surveyor/unparser.rb:32)

Since Rails' Hash#diff has no replacement I cribbed the code from Rails
and added it to Surveyor::Unparser, with only the changes needed to make
it take both hashes as parameters.  Now we'll be OK when Rails removes
Hash#diff.