Rename package name from "analytics" to "segment"

[alvinchow86]

The top-level package name really should be something unique, like segment or segmentio or something. If you have another package or module loaded in your Python load path named analytics, a very common word, there is a name-space collision and it's possible (or very difficult) to resolve in Python. A common case this happens is with Django, if you follow the standard documentation and make an app called analytics that's a top-level import.

# import analytics
import segmentio

This PR renames the module from analytics to segment. I would probably also rename the setuptools name to segment-python or something but left it alone for now.

Related #42

[stevenmiller888]

cc/ @ivolo @calvinfo ^

[alvinchow86]

any thoughts or update about this? the top-level package should really be renamed

related issue #42

[diwu1989]

+1 i think it should be named segmentio

[diwu1989]

it might be even better to just publish a new package completely as segment-python vs analytics-python

[f2prateek]

Closing for #82