Only add routes that are actual names

If Rails version is in Gemfile, use it

not redirects or other calls.

Fixes #395

and process Gemfile before config, because config location
depends on Rails version.

Fixes #398

Add Support For Rails Engines

rails 4 no warning for friendly model in redirect_to (friendly_id gem compatibility)

Add check for detailed exceptions

especially since JSON report requires file name

closes #391

`to_json` is safe in Rails 4

this was supposed to be part of 5ffafd80

Do not warn about XSS with `to_json` in Rails 4

Add option to set table width limit in text output

Remove fuzzy matching for attr_accessible attributes

in practice, this ends up with annoying false positives

Conflicts:
	lib/brakeman/checks/check_model_attr_accessible.rb

Conflicts:
	test/tests/rails31.rb

this changes the default width from 80 to 100

Do not warn on "dangerous" attributes using roles

in particular, don't try to retroactively build call chain.
Fixes #385