BUG: Remove unused imports and rename variable
BUG: Remove more unused imports
STY: Rename variable so it is not redifined
STY/BUG: Remove unused imports

Fix #547
ENH: Speed-up small code snippet:

Using numpy better, let's speed up by a lot!

In [5]: %timeit old()
10000 loops, best of 3: 116 µs per loop

In [6]: %timeit new()
100000 loops, best of 3: 4.47 µs per loop

Thanks @adamrp
MAINT: remove unnecessary extra dimension from procrustes
MAINT: compute frobenius norm more efficiently
BUG: Force dtype of ones to int64
Merge pull request #552 from argriffing/procrustes-frobenius

MAINT: compute frobenius norm more efficiently
BUG: Figure out which version of flake8 is running
ENH: Add pyflakes to the requirements
(-1)*ENH: Add error to see if flake8 catches it
STY: Fix PEP8 issue
BUG: Move flake8 and pyflakes to pip
ENH: Remove unused import
ENH: Remove unused statement in .travis.yml
Merge branch 'master' of git://github.com/biocore/scikit-bio into flake8-errors
Merge pull request #548 from ElDeveloper/flake8-errors

STY: Fix flake8 errors
ENH: Add strict parameter to filter

The strict parameter will ignore IDs that are not found in the distance
matrix.
TST: Add tests for strict filtering