Updated plugin form setting fields.

Resolved #19. Merged CAS parameters (Hostname, Port, path) into one field.
Wrote a parsing function to parse the new field. Same for LDAP parameters.

Conflicts:
	wordpress-cas-client.php
Merge pull request #41 from TriptiSharma/issue-19

Verified that LDAP URI is including LDAP when not included, port is being added, CAS Server is listed as URI,  CAS.php path is being auto populated,.  However, CAS.php is not being saved unless user hit the save button. This exposes a problem because CAS plugin won't work (see issue #44).