[Bug] Centered "Fixed" text within Symbol resizing to custom width
Previously I've been using an Alignment Fixed text layer within buttons and the Resize settings set to scale with the button so that on resize in layout it's easy to set button width by detecting at which point the text wraps. i.e. the Fixed alignment combined with Resize rules helps maintain padding when a user doesn't have the plugin.

After the update the button symbol can no longer change width to account for a longer label, only height. Setting the text to Alignment Auto seems to fix this, but then other users without the plugin lose the ability to size accordingly. The previous version seemed to handle this case correctly.

<img width="390" alt="screen shot 2018-02-13 at 11 32 34 am" src="https://user-images.githubusercontent.com/1437078/36164454-fe15f81a-10b1-11e8-930c-a12cfc7a470e.png">

<img width="193" alt="screen shot 2018-02-13 at 11 35 45 am" src="https://user-images.githubusercontent.com/1437078/36164484-1318fa64-10b2-11e8-8ff9-fe843d889ef5.png">

