#38 String pool uses memory with linked list

[J. Scott Edwards]

The STRING_POOL class uses up memory because it uses a
linked_list to store the strings. Each time a string
is added to the list, it stores it back into a linked
list which allocates memory for the link entry. So for
example everytime an integer is printed, it allocates
memory because it uses the string_pool to convert the
integer to a string.