WIP: auto-scaler proposal

## Abstract
Auto-scaling is a data-driven feature that allows users to increase or decrease capacity as needed by controlling the 
number of pods deployed within the system automatically.  

## Motivation

Applications experience peaks and valleys in usage.  In order to respond to increases and decreases in load, administrators 
scale their applications by adding computing resources.  In the cloud computing environment this can be 
done automatically based on statistical analysis and thresholds.

[Proposal](https://github.com/pweil-/kubernetes/blob/0bd1cfb7b15c3717c6787bdc5dba16fce79544d4/docs/proposals/autoscaling.md)
Will update the proposal with info from https://github.com/GoogleCloudPlatform/kubernetes/pull/2863#issuecomment-66939472

Allowing the user to define the comparison and scale increment will allow them to scale up or down with a single `ShouldScale` interface by passing the scale increment to the `resize` endpoint (negative values account for the scale down scenario).