TST: Add support for NumPy's in-session testing

Tests can now be executed from within a(n) (I)Python session by calling
something like:

>>> import skbio
>>> skbio.test()
.......... .....
XXX Tests OK
>>> skbio.parse.sequences.test()
........ .......

This is as suggested by NumPy's guidelines, see [1] for more information
about this configuraion.

Notes:

The only odd thing is that if we add the few configuration lines as
suggested by Numpy's documentation, then we end up with an error like
this:

>>> import skbio
>>> skbio.test()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/yoshikivazquezbaeza/git_sw/scikit-bio/skbio/__init__.py", line 54, in test
    return Tester().test(level, verbosity)
  File "/Users/yoshikivazquezbaeza/.virtualenvs/skbio/lib/python2.7/site-packages/numpy/testing/nosetester.py", line 146, in __init__
    raise AssertionError
AssertionError
>>>

That's the reason why we don't have the function calls wrapped around
another function.

[1] https://github.com/numpy/numpy/blob/master/doc/TESTS.rst.txt
bug fix, find cache was not forced to be at the root
added bug test, desc of find methods that are based from root and not
STY: Fix copyright notices for new pep8 version (1.5)
STY: space after #
STY: More comments
STY: Use `v not in container` instead of `not v in container`.
STY: Comments and `not in`
MAINT: removed unsued imports and typo in shebang.
STY: setup.py copyright.
STY: remove ### comments ###
STY: Reformatting more comments
STY: final fixes
MAINT: Remove retrieval of tests and data

@Jorge-C noted that there's no need to include the filenames of the
tests in the package_data parameter as there's an __init__.py file being
included in each test suite already. As for the test data, given that
the only module that relies on test data is ordination, it is better to
hard-code the path instead of retrieving the information module per
moduel.

Fixes #247