Change valgrind makefile option to display detailed leak info.

Set --leak-check=full.
Eliminate memory leaks from my bstr_tests.c file.

Added a bunch of bdestroy and bstrListDestroy to free memory
which is not used. WARNING THIS CODE IS HIGHLY NONMODULAR AND BAD
RIGHT NOW.
Implement hashmap.c, hashmap.h and hashmap_tests.c directly from LCHTW

Retyped the LCTHW exercise 37 verbatim and compiled the result
so that the unit tests worked.