be abble to send a json response with a 404 handler 

use case rest api:
 be abble to send a json response without to create a template, shorcut the rendering.

```
route file:
 {404, [{controller, "v1"}, {action, "not_found"}]}.
```

```erlang
not_found('GET', _) ->
    {404, jsx:encode([{error, <<"Invalid Request">>}]), [{"Content-type","application/json"}]}.
```
Document template_auto_escape.
Support specs with Module:Type().
Send a server error (500) when an action fails.
Merge pull request #514 from fdevibe/boss_doc_module_type_support

merged, thanks
Merge pull request #513 from fdevibe/document_template_auto_escape

Document template_auto_escape.
Merge pull request #516 from fdevibe/send_500_when_action_fails

Send a server error (500) when an action fails.
Merge pull request #506 from mihawk/patch-19

be abble to send a json response with a 404 handler
Merge branch 'master' of https://github.com/ChicagoBoss/ChicagoBoss into format_stacktraces_in_logs

* 'master' of https://github.com/ChicagoBoss/ChicagoBoss:
  Send a server error (500) when an action fails.
  Support specs with Module:Type().
  Document template_auto_escape.
  be abble to send a json response with a 404 handler

Conflicts:
	src/boss/boss_web_controller.erl
Rename multiline_stack_traces to log_stack_multiline.