undo incorrect coercion removal - passing through C types might be required due to low-level value conversions

Conflicts:
	CHANGES.rst

* Add Python 3.5 to the build matrix
* Rework helper build script (copied from mpi4py)

only look at yield statements and not arbitrary yield expressions when inlining generator expressions

Conflicts:
	CHANGES.rst
	Cython/Shadow.py

guess longness suffix of negative decimal integer literals based on their type to prevent the C compiler from truncating their value range