Add getAll(keys) method

[TheTekton]

Retrieving iOS plist values is done synchronously. We can simply return the dictionary.

• Add getAll(keys) method.
• Ensure iOS/Android APIs match.

[CubeSugar]

Thx for your pr.

1. I do not think this is a good idea to return the whole infodata.
2. Cause this lib is for both iOS and Android platform. I prefer to offer the same api

Any advice is welcome

[TheTekton]

I'll look at improving this. Made this PR, at the end of the night, as a quick/dirty hack for accessing a build environment variable from an iOS plist. react-native core doesn't set a 'staging' NODE_ENV value, using this library to workaround that limitation.

1. I do not think this is a good idea to return the whole infodata.

• Will look into simply providing a separate method for that. Perhaps a getAll(keys) method.

2. Cause this lib is for both iOS and Android platform. I prefer to offer the same api

• Agreed. Will make sure to update with matching APIs. Not currently setup for Android dev, but will test once setup.