added module docstring
more doc bits
iter_ is tracked during execution
more docs
sphinx is pain:
doc additions
ENH: Add cythonized subsample
ENH: Allow it to overwrite the pure Python implementation.
TST: Allow testing of both modules
ENH: Add C source code.
ENH: Installation
MAINT: Add future to requirements.

(https://github.com/PythonCharmers/python-future)
TST: Fix travis
BUG: nose should use the installed skbio

nose was importing skbio from the source directory, not from where
pip was installing it, so now that there's a compiled module it doesn't work.

Fixed by installing in-place (aka develop/edit mode).
ENH: Add generic get_data_path function.

CPython docs warn that inspect.currentframe "relies on Python stack
frame support in the interpreter, which isn’t guaranteed to exist in all
implementations of Python." However, I tested this in PyPy too and it
works. Yeah!
STY: pep8
TST: Replace get_data_path
STY: remove extra line (thanks @wasade)
ENH: 15% more speed (thanks @wasade).
MAINT: tidy up declarations, including right types for indices.