Fix basic.js and implement relayd for bridge configs

[lantis1008]

• Basic.js should now behave correctly under all configuration types.
• Bridge configs are now implemented using relayd. Router IP should be DIFFERENT to AP subnet. I haven't changed the translation files to reflect this yet.

Please thoroughly test this patch, i've done my best to make sure it is ready.

[lantis1008]

this line is no good. should be something like

uci.set("firewall", "@zone[0]", "network", "lan wwan");

Need to test whether @zone[0] works all the time, which i suspect it doesn't. May need a better way of identifying the correct config section.

[lantis1008]

Fixes #504 . Still needs fixing on the firewall script before it is merged. Apologies.

[lantis1008]

Firewall rules should now work properly.

[ericpaulbishop]

I've tested this and, I couldn't find any issues. Good job!

I have this nagging suspicion that I've missed something, given how complex this is, and I'm not sure I want to do a release quite yet (though we're overdue for one), but this looks very, very good. Thank you.