[PLINK-316] Create static pool of PicketLink STS clients to improve
performance of login modules
[BZ1069126] enhancemenents to STS client pool

Conflicts:
	modules/federation/src/main/java/org/picketlink/identity/federation/core/wstrust/STSClientFactory.java
Merge pull request #290 from pskopek/eap-fixies

The latest fixies from EAP 6.3 branch