Add file name in the output of script/runner

Hi,

when you run some script with script/runner and some kind of error happens the output is something like this:

--- test.rb --- raise 'bad bad bad' --- eof ---

$ script/runner lib/test.rb /Library/Ruby/Gems/1.8/gems/rails-2.1.0/lib/commands/runner.rb:45: (eval):2: bad bad bad (RuntimeError)   from /Library/Ruby/Site/1.8/rubygems/custom_require.rb:27:in `eval'   from /Library/Ruby/Gems/1.8/gems/rails-2.1.0/lib/commands/runner.rb: 45   from /Library/Ruby/Site/1.8/rubygems/custom_require.rb:27:in `gem_original_require'   from /Library/Ruby/Site/1.8/rubygems/custom_require.rb:27:in `require'   from script/runner:3

This little patch <http://rails.lighthouseapp.com/projects/8994/ tickets/752-add-file-name-in-script-runner> change this behaviour to work like this:

$ script/runner lib/test.rb lib/test.rb:1: bad bad bad (RuntimeError)   from /Library/Ruby/Site/1.8/rubygems/custom_require.rb:27:in `eval'   from /Users/daniel/programacion/cosas-rails/test_app_2_1_0/vendor/ rails/railties/lib/commands/runner.rb:45   from /Library/Ruby/Site/1.8/rubygems/custom_require.rb:27:in `gem_original_require'   from /Library/Ruby/Site/1.8/rubygems/custom_require.rb:27:in `require'   from script/runner:3

Which is a little more useful (specially the line information).

It's only a one line enhancement. Do somebody have any feedback?

Thanks.