Add option for specifying a local server api address

[dmiddlecamp]

No description provided.

[ScruffR]

I'm tacking a stab at this in my ExtTinkerApp and I made the prod_hostname and api_host_port already configurable on an activity_alter_host that goes along the design pattern of activity_sign_up and activity_log_in and is accessible from these two activities.

The values entered are then stored across sessions in the Android DB. If the input fields are left blank, the default settings will be used again.

But since I'm not going to set up my own server, I'm not sure if these are actually the only addresses/ports that have to be switched. I'd guess the sign up/log in would be done by different servers, too. What other values would I have to expose for user configuration.

And who would be willing to test my version on an "local" server, once I'm done?