Added the pep8 test to travis. All the warnings are disabled and only a few error checks are enabled.

Type annotation pyi file and tests (II)

Added a make.bat to be able to build the docs on Windows too.

Disable failing OpenMP tests in Py3.4 on MSVC, probably an old compiler version on appveyor (and I don't feel like fixing it before Py3.4 goes EoL).
Closes #2489.

Closes #2489.

Moving compilation from the reference guide to the userguide Part 4

Add NPY_CASTING

Add `typeobj` to `dtype`

Add Python Raw memory helper functions

See #2528.

WIP: MAINT: avoid numpy internals in {sg}et_array_base

Remove duplicated C compiler option from tests that is already set by the test runner via the cpp11 tag.