www/py3-requests

Convert Python ports to FLAVORS.

Ports using USE_PYTHON=distutils are now flavored.  They will
  automatically get flavors (py27, py34, py35, py36) depending on what
  versions they support.

  There is also a USE_PYTHON=flavors for ports that do not use distutils
  but need FLAVORS to be set.  A USE_PYTHON=noflavors can be set if
  using distutils but flavors are not wanted.

  A new USE_PYTHON=optsuffix that will add PYTHON_PKGNAMESUFFIX has been
  added to cope with Python ports that did not have the Python
  PKGNAMEPREFIX but are flavored.

  USES=python now also exports a PY_FLAVOR variable that contains the
  current python flavor.  It can be used in dependency lines when the
  port itself is not python flavored.  For example, deskutils/calibre.

  By default, all the flavors are generated.  To only generate flavors
  for the versions in PYTHON2_DEFAULT and PYTHON3_DEFAULT, define
  BUILD_DEFAULT_PYTHON_FLAVORS in your make.conf.

  In all the ports with Python dependencies, the *_DEPENDS entries MUST
  end with the flavor so that the framework knows which to build/use.
  This is done by appending '@${PY_FLAVOR}' after the origin (or
  @${FLAVOR} if in a Python module with Python flavors, as the content
  will be the same).  For example:

    RUN_DEPENDS= ${PYTHON_PKGNAMEPREFIX}six>0:devel/py-six@${PY_FLAVOR}

PR:		223071
Reviewed by:	portmgr, python
Sponsored by:	Absolight
Differential Revision:	https://reviews.freebsd.org/D12464

www/py3-requests: Update slave port to depend on Python 3.x ports

PR:		219833
Approved by:	portmgr blanket

We don't need 4 versions of www/py-requests, 2 are enough

textproc/py3-asciinema: revive and update port

Upstream switched back to python and only supports python 3.x, so revive the
python version of this port and update it. While here, mark the old version
deprecated and create the py3?-requests ports needed as dependencies.