More efficient Tries/DAWGs

[almondtools]

The current trie actually is a directed acyclic word graph (DAWG), yet we have algorithms that do not depend on this:

• Set-Horspool and Wu-Manber need simple tries (can be implemented more efficiently as double array)
• Aho-Corasick needs a trie with support links (can also be implemented as double array, but needs additional structure for support links
• (Set) Backward Oracle Matching uses a factor oracle base on a DAWG, so we will need this implementation at least here

Consequently each algorithm should use the best optimized variant instead of all depending on a DAWG (which is currently labeled trie).