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.
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.
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.
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
Merge branch 'issue-16' of https://github.com/shawn-bellevuecollege/wordpress-cas-client into shawn-bellevuecollege-issue-16
Removing comment line so password is not stored