MacOS App fails on second run

[kevinwright]

macOS High Sierra builder-phoenix 1.14.6 nw.js 0.29.1

The packaged app runs just fine... the first time I try I get the usual question about whether or not I want to run it, because it's a new app, but that's expected.

The second time (and subsequent times) I get "You can't open the application...because it may be damaged or incomplete"

[kevinwright]

Turns out that this happens when version is absent... as it is in the initial examples on the nw.js site. Perhaps the builder should validate instead of just spitting out an invalid plist