Prevent tests from overriding rspec's trap handler

Otherwise you cannot ctrl-C the tests.
Fix rspec warnings
Fix constant redefinition warnings in config tests
Fix warnings caused by reloading Config
Configure correct logger to fix logger trap context warnings
Prevent knife application test from reloading code
Silence warnings when testing deprecated APIs
Remove classes before redefining to fix warnings.
Prevent code reloading in knife tests (fixes constant warnings)
Supress stdout/err output from knife tests