added ModelBackedView
model-backed views

should this logic be handled on controllers instead of views?
showing errors on template
requiring helpers before than anything else
showing errors on template
allowing clientes' email to be null
added new classes folder and requiring it

ModelBackedView didn’t seem right being on helpers/
added array_with_lines helper that shows an array separated by <br />

usage: `{{array_with_lines array}}`
showing errors with new format