Unexpected sizing results when applying text overrides to symbols
# Bug report

Sketch 49.1 + Paddy 1.0.7

I'm having unexpected sizing results when applying text overrides to symbols. Image below.

For context, I'm using the pink spacer rectangles to narrow down the issue. I'm not applying padding to the background or spacing between elements as seen in the layer settings. Ideally, I would use Paddy to create the spacing around the text instead of spacers. I've been doing this with the Autolayout plugin for a while, but using one plugin would be even better. The idea is the maintain exact spacing between the elements as text grows from one to many lines as then re-pad the background shape so that I don't have to manually make the symbol/group taller to see all of the content.

In the below example, both groups are the exact same. The second just has more copy in the text boxes and produces the desired result (the box grows vertically).

Happy to add more info if needed. Thanks!

## Expected behavior:

The padding, alignment and spacing of a symbol should be maintained when text is overridden.

## Actual behavior:

The symbol jumps to the left and resizes. Also does not maintain the centering setting.

![example](https://user-images.githubusercontent.com/717668/37623021-b6e394fe-2b99-11e8-8e5c-9b6525e9b4ab.png)

## Steps to reproduce:

Place a clean symbol, override the symbol text and it will jump sideways and grow.

[Paddy-Test-031918.sketch.zip](https://github.com/DWilliames/paddy-sketch-plugin/files/1827008/Paddy-Test-031918.sketch.zip)

Thanks for your time!
