Fix: ht_nbuckets() shouldnt be able to modify the ht obj
Moved malloc to calloc
Added missing frees
Merge pull request #226 from matthiasbeyer/fix-ht_nbuckets_const_params

Fix: ht_nbuckets() arg made const
Merge pull request #227 from TheNeikos/fix-ll_uninit_values

Fix ll uninitialized values in test