DOC/ENH: TreeNode.find_by_id has mention of not caching. Added short cut
DOC: doc and doctest for find_all
TST: tests for TreeNode.find_all
ENH: added TreeNode.find_all code
ENH: TreeNode.find_all supports tips
DOC: dropping 'internal'
Merge branch 'master' of github.com:biocore/scikit-bio into issue344
Merge pull request #589 from wasade/issue344

add TreeNode.find_all