major refactoring of builtin method/function overrides to support explicit function types and utility code dependencies

fix 'self' argument type in generic builtin method overrides, test for None at call time (ticket #571)

--HG--
rename : Cython/Compiler/Dependencies.py => Cython/Build/Dependencies.py

Fill class attributes dict before class creation. Use bindings for class methods.
And use PyCFunction for staticmethods and __new__. Add simple testcase for __metaclass__.
And test for staticmethod as decorator

in pure mode: rename 'with nogil' to 'with cython.nogil', test 'real' pure mode by compiling .py file instead of .pyx file

--HG--
rename : tests/run/pure.pyx => tests/run/pure_py.py