Introduction of a linked list trie!
Instead of storing child pointers as an array on the node,
one child pointer then sibling child nodes are a linked list.
Speed not much changed, huge memory savings!

For standard corpus, 195128 tunes. New:
Real: 145, Private: 143, Virtual: 200, Time: 16:00
Previous:
Real: 415, Private: 413, Virtual: 477, Time: 15:51
Merge branch 'linkedlist' of https://github.com/afandian/tunesearch into linkedlist