Flexible testing for toWarn()
Revert "Remove this-binding; fix"

This reverts commit 17ddfd212f3579d0695009daf013129751197fb8.

Conflicts:
	lib/Spectre/Base.php
Fixed context inheritance
Fixed helpers
White space
Fixed support for passing context within callbacks
Fixed inject() into invoke()
Fixed pending specs and empty locals
Rename
Adds more core-specs
Organize specs