disable self-argument extraction for lambda functions to revert to old "self in args" argument parsing behaviour

re-enable "profile" and "linetrace" directives at class/function level to allow switching it on and off for specific code sections

Use global constants for default arguments of cpdef functions/methods and def methods in cdef classes as using the CyFunction defaults requires passing the CyFunction as self (which we currently don't do for methods in cdef classes).
Properly fixing this requires changing the call signature of CyFunction.

use global constants for default arguments of cpdef functions (which are static C functions internally)

Re-use, rather than duplicate, error exit code.

This it less important than in Py3 as most optimisable cases are already covered by PyInt, but long objects might still pop up arbitrarily in Py2, so it might be worth it.

re-enable PyMethodDef declarations of Python methods in cdef classes as we cannot currently generate CyFunctions for cpdef methods

enables line tracing etc.

Closes #1438.