This is two changes:
Replacing all usages of SimpleLogger with it's interface SimpleLogging which makes it easier to swap out loggers going forward
Nukes SimpleLogger in favor of StructuredLogger which allows us to better analyze logs in our log management system we choose.
Add Apache 2 license and Hootsuite copyright to all golang
files. Add a disclaimer that the files have been modified
hereafter by contributors to this repo in order to abide
by the Apache 2 license requirements.
