Allow initialization to be performed only once
Initialize Neko on start of every activity
Don't rebind *activity* when in on-ui

This is a step to eliminate activity passing via dynamic binding.
Make fn public for external macro users to work
Move all initialization to neko.init/init

Also pass device port from lein-droid.
Deprecate neko.application namespace
Call activity initialization at activity start
Minor fixes in compliment sources
Prepare 3.0.0-beta6 release