`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

fixes #372

Ignore warnings in rescans and hardcore mode

fixes #381

fixes #382

Ignore warnings in tabs output if configured to do so

Don't abort route processing on variable controller names

Changed all instances of the load_dependency method

Fixes #373

Update guard-brakeman link

[ci skip]