Added Unit Testing for URL Generation + ISSUE-102

**Updated Unit Testing to use isolation mode**
* Allows testing with different defined constants
* Allows testing with different files loaded (functions, classes, etc)
* Refactored existing support and test classes

**Added Unit Tests for URL Generation**
* Catalog URL Generation (from catalog and admin)
* Catalog SEFU URL Generation (from catalog and admin)
* Admin URL Generation (from admin)

**Addressed ISSUE-102 (Generation of admin URLs)**
* Removes extraneous &amp; and ? at the start or end

**Other Changes (Generation of admin URLs)**
* Refactored name, parameters, and deprecated old function
* Added phpdocs for both functions (new and deprecated)
* Added notify hook to allow observing URL generation
* Removes all duplicate &amp; and &amp;amp; (2 or more in sequence)
* Applied patch for checking SID
* Changes all &amp; characters into &amp;amp;

**Other Changes (Generation of catalog URLs)**
* Removes all duplicate &amp; and &amp;amp; (2 or more in sequence)