Fix `redirect_to` false negative with only_path

Fixes #120

Relative paths for reports

High confidence warnings on `to_json`

Makes slightly more sense and doesn't seem to refer
to application path

Set ActiveSupport.escape_html_entities_in_json=true in versions >= 2.1.0 for autoescaping on a to_json call.

User could compare with the **baseline** json file ignore base directory.

Track render chain for templates

Allow Brakeman to be run without tty

This tests when you have a partial that is rendered from
more than one controller action, which in the past would cause
rendered partials to be overwritten, possibly hiding warnings

There was a bit of a logic error here, because a
warning might be detected as a duplicate in
`check_for_immediate_xss`, causing it to return 'false'
and then the check would go ahead and process the `raw` call.
This would result in 'weak' confidence warnings that were
duplicates of 'high' confidence warnings.

instead of a single caller

User can use the brakeman on admin tools which has no tty support

Fix --rake when output to file(s)

fixes #130

A little bit better error visibility

Treat model attribute as immediate value in `or` expressions

Conflicts:
	lib/brakeman/checks/base_check.rb

Remove method_missing behavior from Sexp

Conflicts:
	lib/ruby_parser/bm_sexp.rb

Add convenience methods for Sexp nodes

instead of having to use array-like indexing which is
hard to read and hard to remember

Move along, nothing to see here! No idea how this snuck in.

`BaseCheck#has_immediate_model?` will return true if a model attribute
is found in an `or` expression, just like
`BaseCheck#has_immediate_user_input?` does for everything else.