Fix #40 - LDAP user/pass not saving

LDAP username & password settings did not seem to be saving to
the database. Added those two fields to the retrieval of
settings (they were missing), but didn't find the save code
before it started working. Jonathan set me up with dev access
to the database at that time, so I'm thinking that something
happened with the DB permissions.
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
Resolve #16 - Secure LDAP connection

Implemented LDAPS connections (on both port 636 & 389).
Began larger refactoring of code by encapsulating LDAP
management into its own class. Also implemented a debug_log()
method to use for non-error log output.
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).
Merge branch 'dev' of https://github.com/BellevueCollege/wordpress-cas-client into issue-40

Conflicts:
	wordpress-cas-client.php

Merged my changes with recent changes made by other developer.
Merge pull request #42 from shawn-bellevuecollege/issue-40

Merge changes fix "LDAP User" and "LDAP Password" fields being saved in
single site installations. This problem does not show up in multisite
installations.

Additionally a new bug under single site installations was discovered
where "CAS Server URI" and "LDAP URI" fields are not being saved. This
bug will be filed separately.
Default cas include path inserted into databases

Resolved #44 - If the CAS Path is null or not setup, code looks for the
default path and if the file exists there it adds the path to the database and
populates the field in the form.
Merge pull request #48 from TriptiSharma/issue-44

Default cas include path inserted into databases
Merged current BellevueCollege code.

Also fixed invalid call to debug_log()
Fix invalid constant

Fixed a constant name change in ldapManager that didn't get
propagated to wordpress-cas-client.
Added new fields to register_settings

Resolved #49 - New fields like casserver, ldapuri were not being saved
since they were not being added to the options list for single site.
Refactored to include logic from commit 64373b3

Commit 64373b3 (pull request #42) broke my current changes for
Issue #16 so in order to resolve the conflicts, I'm merging LDAP
functionality that was added into the ldapManager class.
Moved string literal to a constant.
LDAP Password Encrypted

Resolved #39
Encrypted LDAP password before it gets stored in the database.
Decrypt password after retreiving from database.
Password can be reset but its never visible to the user.
Migrated LDAP functionality into class

Moved majority of LDAP settings and functionality into
ldapManager class.
Added timestamp to debug log.
Merge branch 'issue-49' of https://github.com/TriptiSharma/wordpress-cas-client into issue-16
Merge branch 'issue-39' of https://github.com/TriptiSharma/wordpress-cas-client into issue-16

Conflicts:
	wordpress-cas-client.php
Added '@' to mcrypt function calls

Did this to inhibit display of warning messages in the UI.
Merge branch 'dev' of github.com:BellevueCollege/wordpress-cas-client into issue-16

Conflicts:
	wordpress-cas-client.php