more-itertools dropped Python 2 support with 6.0. The recent upgrade (#5291)
to 7.0 results in the package no longer working under Python 2 and breaks
packages depending on it like pytest.
Split the PKGBUILD up into a Python 2 (5.0) and Python 3 (7.0) version.
Add an epoch to the Python 2 version so that package upgrades work.
* python-bleach: Update to 3.1.0
* python-entrypoints: Update to 0.3
* python-more-itertools: Update to 5.0.0
* python-jupyter-notebook: Update to 5.7.4
* python-jedi: Update to 0.13.2
* python-soupsieve: Update to 1.7.0
* Add two helper macros to the PKGBUILD templates. apply_patch_with_msg applies a patch ensuring a backup is made and with an output message showing the patch being applied to help with debugging. del_file_exists delets files and is meant for where a patch creates new files. Those added files may not be deleted if the PKGBUILD is reran causing patch to fail saying it's already been applied.
Fix the setup-py template to use a _dtoken variable for part of the URL in pypi. Those use a download token for each software package and is unique to EVERY version. Also, use python${pver}-build-${CARCH} consistantly. The CARCH allows us to have for binary versions so that they could be examined if a build problem were to occur and speed up the build.
* Fixed the comment about the source and made a point about downloading from some source such as github instead of pypi.
* mingw-w64-python-more-itertools - 4.2.0, mingw-w64-python-pytest - 3.5.1 - Update to the latest.
