Zoom-in a lot bug.

## What did you do?

Opened demo project -> Line Chart 1. Started zoom-in.

## What did you expect to happen?

Correct zoom-in for y and x axises.

## What happened instead?

If zoom-in a lot x axis values are shifted. During zooming x axis values are correct but after stop zoom-in x axis is shifted.
UPDATED:
Also if zoom-in a lot(about 10-20 times) UI will be blocked.

## Charts Environment

**Charts version/Branch/Commit Number:*1.1.1*
**Xcode version:*9.4.1*
**Swift version:*4.1*
**Platform(s) running Charts:*iOS*
**macOS version running Xcode:*10.13.6 (17G65)*

## Demo Project

You could use demo project from the Charts sources.
Also please see a movie - https://www.dropbox.com/s/vlp9t617vwzk001/charts_zoom-in.mov?dl=0
P.S. May be anyone knows how to limit zoom-in?