Foreground error logs aren't properly parsed.

[Markil3]

Log messages sent from the foreground addon scripts are not properly parsed. Case in point:

BrowserRunner:163 DEBUG - Received update LOG TRACE: [Sending to interface {}, {type=edu.regis.universeplayer.browserCommands.BrowserError, name=TypeError, message=can't access property "artists", data.album is undefined, fileName=moz-extension://5e27068f-f1b0-4453-923b-b491beb01860/youtube.js, lineNumber=129.0, columnNumber=17.0, stack=getAutogeneratedMetadata/<@moz-extension://5e27068f-f1b0-4453-923b-b491beb01860/youtube.js:129:17
getAutogeneratedMetadata@moz-extension://5e27068f-f1b0-4453-923b-b491beb01860/youtube.js:117:10
getSongData@moz-extension://5e27068f-f1b0-4453-923b-b491beb01860/youtube.js:39:16
handleMessage@moz-extension://5e27068f-f1b0-4453-923b-b491beb01860/foreground.js:46:20
@moz-extension://5e27068f-f1b0-4453-923b-b491beb01860/foreground.js:136:41
}]