eliminated the use of the $_SERVER superglobal;fixed some spacing; fixed comments for Doxygen; added a few TODO items
refactored getMementoFromDb into a dispatcher that calls 3 functions to do its work; this way it's a bit cleaner; unit tests for getMementoDbOrder and buildMementoDbCondition to follow, once I figure out how to mock a DatabaseBase object
added unit tests for new functions; changed getMementoDbOrder name to getMementoDbSortOrder because it's more descriptive;created mock objects and functions for unit tests