Make the stack trace cleaner IE9 compatible (err.stack is null)
Make the stack trace cleaner IE9 compatible (err.stack is null)

MithrilJS/mithril.js,impinball/mithril.js,pygy/mithril.js,lhorie/mithril.js,pygy/mithril.js,barneycarroll/mithril.js,impinball/mithril.js,lhorie/mithril.js,MithrilJS/mithril.js,barneycarroll/mithril.js