Added a NULL check
Merge pull request #214 from TheNeikos/fix-avl_find

Added a NULL check to avl_find
Added ht test suite with basic init/destroy test
Added test for allocating more than just 2 buckets
Added ht test: small table, few values
Outsourced generic insert testing code into function
Added ht test: big table, few values
Added ht test: small table, much values
Added ht test: big table, much values
Moved from 4 tests to one loop test with parameter table
Moved static helper back to actual test function
Added test case for adding to suite
Add: More test parameters
Do not use (kind of) random values here
Fix: Name of loop test: We insert distinct values
Removed inserting params for MUCH inserted values
Fixup: Indexing