update README for new config/init pattern

This reworks the README to instruct how to configure assert using the
new config/init pattern.
added the config/init pattern for initializing Assert

This removes all the crappy setup files and puts the init logic
in the CLIRunner class.  This also centralizes all settings on a
Config singleton.  This is the central place all settings are read
from and where User, Local, CLI, and ENV settings will be applied.
Merge pull request #106 from redding/kr-configinit

use a config/init pattern