[WSS-495] - Add support to configure the digest method used for SAML Assertions


Conflicts:
	src/main/java/org/apache/ws/security/saml/ext/SAMLCallback.java
	src/test/java/org/apache/ws/security/saml/ext/AssertionSigningTest.java
	ws-security-dom/src/main/java/org/apache/wss4j/dom/action/SAMLTokenSignedAction.java
	ws-security-stax/src/main/java/org/apache/wss4j/stax/impl/processor/output/SAMLTokenOutputProcessor.java

git-svn-id: https://svn.apache.org/repos/asf/webservices/wss4j/branches/1_6_x-fixes@1581775 13f79535-47bb-0310-9956-ffa450edef68