run tests with negative inputs for BCD functions
comment about a good reference for algorithms
added LPA_BCDmultiply() & LPA_BCDfreeNumber()
fixed valgrind errors: using uninitialised memory (negative was always set, LPA_BCD_invert read off the end of the array)
added LPA_INT_freeNumber()
tests for LPA_BCD_multiply()
valgrind errors about leaking memory, free the temp test numbers when they get re-created