Updates for React Native 0.60

[brody2consult]

• update *Dependencies in generated package.json - update not needed since generated package.json already has a range that covered 0.60; it is desired to drop support for 0.59 when it is not needed someday in the future
• use a newer Android tools version such as 3.4.1 in build.gradle (as proposed in PR Gradle updates in android.js #24)
• test without —view option on iOS & Android
• test with —view option on iOS & Android

Note that use with React Native 0.60 is not yet expected to work with react-native-windows, which seems to be stuck on 0.58 for .NET and 0.59 for C++ 0.59 for both .NET and C++ (see #23) or Expo.

[brody2consult]

Closing as resolved