ENH: checklist.py now enforces a minimal API in tests
MAINT: Unneeded else clause, no longer prefers alternate import if not any deeper
MAINT: Code cleanup for APIRegressionValidator
TST: all tests use minimum API
MAINT: corrections to checklist.py
DOC: explanation of minimally deep api imports in tests
DOC: explanation of minimally deep api imports in tests
Merge branch 'EnforceAPI' of https://github.com/ebolyen/scikit-bio into EnforceAPI

Conflicts:
	doc/source/development/coding_guidelines.rst
Merge pull request #543 from ebolyen/EnforceAPI

ENH: checklist.py now enforces a minimal API in tests
API: removed math, skbio.math.$ -> skbio.$
TST: corrected import path for test_subsample.py
TST: moved test_subsample.py as nose ignores any subpackage with an `_`
API: made ordination.utils private
MAINT: pep8
MAINT: pep8
Remove skbio.app subpackage in favor of burrito.
MAINT: added failing tests where input type has been changed for input in private functions
MAINT: updated type for inputs to private functions
ENH: updated to support comptuing scores and traceback from Alignment objects
ENH: updated traceback to work from Alingment objects