more visibly mark for-from loop as deprecated in the docs

--HG--
extra : rebase_source : 305a362b2f79e4b7982a188ff5912a6621ea56a7
Document cythonize accepts Extension arguments.
Update compilation instructions.
Even more clarification on cythonize().
add explicit section on Cython's Python string types
add hint on when C++ strings are useful
fix sphinx markup
update userguide to use cythonize() for building
rst fix
remove another reference to the old distutils build (in quickstart!) and clarify the description of the Sage notebook a bit
whitespace
Merge branch '0.19.x' of git+ssh://github.com/cython/cython into 0.19.x