Create TreeTest; fix issues found in tree/topology

- mlmodel test additional features / finishing TODO list
- alphabet additional features to support unit tests
- tree fixes derived from unit tests
- initialize random module in internal.ml

- unit tests for alphabet and tree updated/created
added META file for ocamlfind install/uninstall
Merge branch 'master' of https://github.com/nrlucaroni/phylocaml
Merge ../Phylocaml
add treeTest module for unit testing trees
Merge ../Phylocaml