Made a few improvements to struct and mem

Memory management improvements.  Malloc utilized more consistently.
Eliminated redundant lines of code by moving them to struct's
functionality.
Refactoring and queue improvements

-Creation of the queue has been greatly simplified
-Lots of redundant and confusing code removed
Struct-pointer bug addressed, activity type string

-Allow printing the activity type by creating function that converts
numerical type value to the appropriate activity string.
-Correctly instantiate the array of pointers to the activity lists.