Re-evaluate the need for supporting reachability

[sakuraehikaru]

My feeling is that network reachability is different enough from accessing REST APIs that there isn’t much value in just building it into SCNetworkAPI. If we find we are writing a lot of per-app reachability code that is the same it might be a candidate for a separate shared library, however, I ALSO don’t feel like we are writing a lot of sharable code in that area, and that the reachability libraries that are our there already are probably enough. Looking at Spies as an example there’s only like 20 or 30 lines of reachability related code outside of the ReachabilitySwift pod, and the bulk of that is very app specific.

[brendanlensink]

To be clear, we currently don't have any support for network reachability built into Netable, and this issue is proposing that we evaluate if we feel like we should add it or not.