fixes #38: update call to footer method
APST-822: allow external invoice renderer engines
Merge branch 'development' of github.com:NetresearchAppFactory/firegento-pdf into development
allow to print creditmemos with no items
Unified invoice and creditmemo item rendering
Merge pull request #40 from NetresearchAppFactory/development

fixes #38: update call to footer method
Merge pull request #43 from sprankhub/creditmemo-patch

Allow to print creditmemos with no items
Merge pull request #44 from sprankhub/creditmemo-patch2

Unified invoice and creditmemo item rendering