speed up delegation of generators and coroutines a little by avoiding an indirect C call in favour of a directly visible recursive call

make current scope available to FunctionState and CCodeWriter to give access to variable types from AnnotationCCodeWriter

Fix syntax error in memoryview userguide documentation.

Conflicts:
	CHANGES.rst
	docs/src/reference/compilation.rst

let's see if the list order of the python releases makes a difference for the execution order in travis