First crack at making the suffix tree interface closer to the other modules. Especially, make the node and tree opaque since we may need to significantly change those implementations.
Edit equivalence class table code to handle new SuffixTree interface.
Change KK algorithm code to use new SuffixTree interface. Also delete code only needed for old equivalence class table interface.
Change LCA code to use new SuffixTree interface.
Fix little memory leak in equiv class array tests.
Update tests to use new SuffixTree interface.