app-exists doesn't detect Applications in the User's local directory

[WorkInProgress-Development]

Issue occurs as part of PR #4, and discovered whilst investigating will-stone/browserosaurus#399
The error is specifically on line 10 of index.js, as node does not expand tildes (nodejs/node#684).
From my limited understanding of node, and testing locally, process.env.HOME has a function equivalent to the tilde, so this should be an easy fix.
Pull request incoming.

[WorkInProgress-Development]

Alternatively, you could use sindresorhus/untildify.

Edit: which I am now realising is one of your own libraries.