Security warning when importing unsigned TokenScript definitions

When importing unsigned TokenScript files, at least on Android, there is no confirmation step. It wouldn't be hard to imagine this being used in a phishing scam.

I recommend 1-2 things to mitigate this risk:

1. Implement a warning dialog when importing unsigned/unverified TokenScript definitions into AlphaWallet.
2. Restrict manual import to devices with developer mode enabled. I know this is at least possible in Android. This would be in addition to above to add an extra layer of security.