Fixes #69

Thanks @antage

Support multiple output files with different formats

Rescanning of templates doesn't pass through the same "filter" as the in...

/Users/neilm/workspace/brakeman/lib/brakeman/scanner.rb:302:in `process_template': undefined method `[]' for nil:NilClass (NoMethodError)

Debated between filtering this in the process_template method, decided to filter BEFORE calling process_template, decided to leave it here to bypass the other login in rescan_template

Add check for Object#send with user input.

during progress. I don't really know why this was there...

because when the get re-processed the module information
is lost (just class code is stored)

Add moar test cases

Model.send(params[:method]) == bad

[ci skip]

Use old ruby_parser (2.3.1) for Ruby 1.8 parsing

Fix handling of Erubis templates with xss escaping via rails_xss or Rails 3 (but Rails 3 should not really be affected)

Improved dynamic render check, ignore condition in if statements when looking for user input.

either with rails_xss or Rails 3.
This was broken when Brakeman's Erubis output was
changed to match what rails_xss does. Unfortunately, that
broke the ErubisTemplateProcessor such that NO output
was detected. This should fix that.

Note that this code detects auto-escaping by the output variable.
@output_buffer is used in Brakeman's Erubis classes. _buf will
only show up if someone is using Erubis with auto-escaping turned
off.

Standardize output of stack trace in 1.8 and 1.9
but only when using debug option

Thanks @PragTob