Listen NetInfo connectionChange event (change deprecated)

[ghost]

Fixes #75

[kfiroo]

@kytwb Great, thanks!
Just a quick question, would that cause a problem for users with lower versions of RN? (I think it's polite to support at least 1-2 previous versions)

[ghost]

@kfiroo I'll check and make it backward compatible if possible.
If not possible, what should I do? Follow semver and major/minor the version?

[kfiroo]

@kytwb Thanks!
If you can't make it backward compatible we should merge it after the 1.4 version, which already forces users to upgrade

[chrusart]

Will this work?
facebook/react-native#12503
just check if RN >= 0.48.0 then use connectionChange event name
its just a lot of warnings in console, but probably should be made in normal a way, changed in 1.4.