Fixes issue caused by "magical" iteration shorthand. Was flawed logic.

- the_index = (the_index + 1) + (the_index % self.table_size)
+ the_index += 1
+ the_index %= self.table_size
Adds failing test to replicate insert/delete->find w/ multiples of desired hash keys
HashTable Implements fix for "Empty != Deleted" issue. 9a0f3f2/533f99d

- On "delete" set slot to False rather than None. Slots are not reusable.
- Test passing! See 9a0f3f2 and 533f99d