DSS-219: Support of the counter-signatures
Merge remote-tracking branch 'origin/develop' into develop

Conflicts:
	apps/dss/core/dss-document/src/main/java/eu/europa/ec/markt/dss/signature/xades/CounterSignatureBuilder.java
	apps/dss/core/dss-document/src/main/java/eu/europa/ec/markt/dss/signature/xades/XAdESService.java
DSS-219: Support of the counter-signatures