Logistic Regression [Python]

#### This issue is about [Logistic Regression](http://machinelearningmastery.com/logistic-regression-tutorial-for-machine-learning/).

- [x] Issue Title is in form `Algo/DS Name [Language]`.
- [x] I searched or browsed the repo’s other issues to ensure this is not a duplicate.
- [x] This Algo/DS is worth adding to this repository.
- [x] Assign this issue to me (I want to work on this).
- [x] I ensure that I am not already assigned to 2 or more issues.
- [x] I will send my PR only after I'm assigned to this issue by any maintainer.
- [x] I understand that I will be unassigned from this issue if I fail to send a PR for this within a week.

Start by reviewing the repository's existing algorithm implementations and Python conventions, then consult the linked Logistic Regression tutorial for the intended scope. Done means adding a Logistic Regression implementation in the repository with behavior consistent with its existing algorithms.

Written by the indexing model from the issue text.