CAS-1305: Create cas-server-webapp-support module

first commit
Merge remote-tracking branch 'upstream/master' into CAS-1305
CAS-1305: Create cas-server-webapp-support module

Updates after @battags' code review
Deleted CredentialsToLDAPAttributePrincipalResolver.java
Deleted CredentialsToLDAPAttributePrincipalResolver.java
Deleted CredentialsToLDAPAttributePrincipalResolver.java
Remove file that only differs in case to fix CI build.
Merge pull request #273 from leleuj/CAS-1305

CAS-1305: Create cas-server-webapp-support module
CAS-1305 Restore jstl and standard taglib dependencies.
CAS-1305 Declare runtime scope for jstl/taglib dependencies.
CAS-1053 Switch to Spring EL.
CAS-1219 Check TGT validity at start of login flow.

Replace boolean ticket check state with a tristate action that checks the
flow request context and ticket registry for TGT validity and returns
one of the following events:
1. notExists
2. invalid
3. valid
In the second case the browser cookie is deleted and the ticket is deleted
from the registry (if found).
Merge pull request #275 from serac/CAS-1305

CAS-1305 Restore jstl and standard taglib dependencies.
Merge pull request #276 from serac/CAS-1053

CAS-1053 Switch to Spring EL for parsing Webflow expressions.
Merge branch 'master' of github.com:Jasig/cas into CAS-1219
CAS-1219 Factor out SSO end actions into separate component.

The actions required to end the CAS SSO session have been factored out into
a common component, TerminateSessionAction, that is called from both login
and logout flows at the appropriate time.
CAS-1219 Javadoc improvement recommended in code review.
Merge pull request #277 from serac/CAS-1219

CAS-1219 Perform TGT Validity Check at Start of Login Flow
Clearpass reference to decorated map is incorrect.

The default/sample configuration points to the plain credentials cache for keeping track of the credential, while the actual instance should be the decorated encrypted map.
Merge pull request #279 from Unicon/NOJIRA-CLRPASS-MAPREF

Clearpass reference to decorated map is incorrect.