GUI updates, tabs, modals added

This is the shell for the new gui. work still needs to be done
to make functionality dynamic and operational.
Re-structured code

* Divided client and server code into different files
* Renamed files
* Resolved #52
* Resolved #39 - For single sites the password will now be encrypted and
  stored in the database.
Encapsulating common code into classes

Began the work of refactoring ldap and cas objects into classes so they
can be managed atomically. WARNING: This code contains errors.
Completed current refactoring work.

Fixed a variety of bugs and finally got everything running. Here's a
list of the major code & architectural changes to date:

* added _ldapUser_ class.
* moved cas-related code into its own file & renamed to _casManager_.
    * created wrapper functions in _wordpress-cas-client.php_ so we can
      have more control over how _casManager_ is instantiated, etc.
* moved defines into new _cas-client-constants_ file.
Merge pull request #58 from jonathanwindle/issue-4

* Confirmed 6fb53b5 resolves #52 and #39
* Completed regression testing
* Found bug #59: Plugin generates 2 characters of unexpected output
  during activation
Adding ldap attribute array

See https://github.com/BellevueCollege/wordpress-cas-client/issues/8

NOT TESTED. NOT RUN.
Structure in place for managing user attribute mapping.

I've implemented the majority of the structure needed to support specifying attributes to
map to wordpress profile fields. Next step is to add the UI to add/remove these
settings.
Began wiring LDAP attribute mappings to UI.

What has been done:

* _casManager_, _ldapManager_, etc. have been re-worked to support passing in and parsing of user attributes to be taken from LDAP. _ldapManager_ uses this collection to determine what attributes it will retrieve when getting the user info.
* The HTML @esteen provided has been added to cas-client-ui.php via a new admin-attribute-mapping.php file. (I'll probably want to refactor this to a class at some point.)
    * I've begun wiring up the HTML to display the settings from the config table - with hard-coded placeholders and notes that they need to be replaced with real data.
    * @TriptiSharma and I have spoken about how this is being done, and we should be on the same page.

What needs to be done:

* Finish any UI functionality (e.g. expanding/collapsing, create new, edit existing)
* Save settings to the config table
    * Collect all settings into an array of ldapProfileMapping objects.
    * Save that array to a single database record as JSON (use [json_encode](http://us1.php.net/manual/en/function.json-encode.php) on the array) with the key of _user_attribute_map_.
    * See **casManager::GetMappings()** for examples relating to the 2 previous bullets.
* Add an **LDAP query** to the system-level LDAP settings (this will be made more flexible later).
    * This value will also need to be passed to the _ldapManager_ when it is instantiated. (Currently, this is in the _casManager_ constructor.)
Issue #4

Note: The task is not complete yet. Below are some pieces finished:
- Finished Add, view and edit role functions.