for tracking where a Sexp came from

which looked strange when no warnings were reported but the summary said
there were.

Add option to exit with nonzero exit code when warnings found

Put exit code constant in Brakeman namespace; use Checks#all_warnings, not #warnings ; don't steal the -s option

even when there is no code context to show

Use exit code 3, not 1, when warnings are present to differentiate between exceptions and warnings found

allowing Brakeman to easily be used as a library now

which will bump the confidence to High if t() or translate() are used
in the application.

which fixes #15

to test for absence of a warning

which closes #16

because Rails 2 and 3 need different processors