net/py-rainbowstream: Make pocket (really) optional

rainbowstream has configurable Pocket support (via settings) but declares
the dependency in install_requires, making it a compulsory run-time dependency
checked/varified by setuptools.

When first committed, given the pocket Python package had not yet been ported,
it was (obviously) not included in RUN_DEPENDS, but it was not removed from
setup.py:install_requires, resulting in the following runtime error:

  pkg_resources.DistributionNotFound: The 'pocket' distribution was not found
  and is required by rainbowstream

This could be rectified by the user by installing the package from pip, which
is convenient, but which we explicitly recommend against [1].

This commit patches setup.py moving pocket to setup.py:extras_require and the
main module to conditionally import pocket, instead of failing as follows:

    from pocket import Pocket
  ImportError: No module named pocket

While I'm here:

- Remove upper bound/limit on 3.x version support

[1] See devel/py-pip/pkg-message

PR:		220312
Reported by:	Petr Fischer <petr.fischer me com>
MFH:		2017Q3

net/py-rainbowstream/Makefile

@@ -3,6 +3,7 @@
 
 PORTNAME=	rainbowstream
 PORTVERSION=	1.3.5
+PORTREVISION=	1
 CATEGORIES=	net python
 MASTER_SITES=	CHEESESHOP
 PKGNAMEPREFIX=	${PYTHON_PKGNAMEPREFIX}
@@ -21,8 +22,8 @@ RUN_DEPENDS=	${PYTHON_PKGNAMEPREFIX}dateutil>0:devel/py-dateutil \
 		${PYTHON_PKGNAMEPREFIX}pillow>0:graphics/py-pillow \
 		${PYTHON_PKGNAMEPREFIX}pysocks>0:net/py-pysocks
 
-# Actually 2.7,3.2-3.4
-USES=		python:2.7-3.4
+# Actually 2.7,3.2-
+USES=		python:2.7-
 USE_PYTHON=	autoplist concurrent distutils
 
 NO_ARCH=	yes

net/py-rainbowstream/files/patch-rainbowstream_rainbow.py

@@ -0,0 +1,17 @@
+# Make pocket actually optional
+# https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=220312
+
+--- rainbowstream/rainbow.py.orig	2017-07-03 10:00:26 UTC
++++ rainbowstream/rainbow.py
+@@ -20,7 +20,10 @@ from twitter.oauth import OAuth, read_to
+ from twitter.oauth_dance import oauth_dance
+ from twitter.util import printNicely
+ 
+-from pocket import Pocket
++try:
++    from pocket import Pocket
++except ImportError:
++    pckt = None
+ 
+ from .draw import *
+ from .colors import *

net/py-rainbowstream/files/patch-setup.py

@@ -1,6 +1,9 @@
---- setup.py.orig	2016-08-04 08:41:32 UTC
+# Make pocket actually optional
+# https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=220312
+
+--- setup.py.orig	2016-08-16 14:49:45 UTC
 +++ setup.py
-@@ -9,7 +9,7 @@ version = '1.3.3'
+@@ -15,14 +15,17 @@ version = '1.3.5'
  install_requires = [
      "python-dateutil",
      "arrow",
@@ -9,3 +12,22 @@
      "pyfiglet",
      "twitter",
      "Pillow",
+     "PySocks",
+-    "pocket"
+ ]
+ 
++extras_require = {
++    'pocket': ["pocket"],
++}
++
+ # Default user (considers non virtualenv method)
+ user = os.environ.get('SUDO_USER', os.environ['USER'])
+ 
+@@ -65,6 +68,7 @@ setup(name='rainbowstream',
+       include_package_data=True,
+       zip_safe=True,
+       install_requires=install_requires,
++      extras_require=extras_require,
+       entry_points="""
+       # -*- Entry points: -*-
+       [console_scripts]