add / update recipes and build changes for Python 3.6.6 compatibility (#315)

* add / update recipes and build changes for Python 3.6.6 compatibility
* include Python 3 apt packages in travis build script
* use Python 3.6 in Travis
* Enable _blake2 and _sha3 in Python 3. Remove unnecessary files.
* change zope.interface version
* update cffi version

p4a/pythonforandroid/logger.py

@@ -1,4 +1,3 @@
-
 import logging
 import os
 import re
@@ -16,7 +15,7 @@ if not six.PY3:
     stderr = codecs.getwriter('utf8')(stderr)
 
 if six.PY2:
-    unistr = unicode
+    unistr = unicode  # noqa F821
 else:
     unistr = str
 
@@ -43,6 +42,7 @@ class LevelDifferentiatingFormatter(logging.Formatter):
                 Err_Style.RESET_ALL) + record.msg
         return super(LevelDifferentiatingFormatter, self).format(record)
 
+
 logger = logging.getLogger('p4a')
 if not hasattr(logger, 'touched'):  # Necessary as importlib reloads
                                     # this, which would add a second
@@ -72,6 +72,7 @@ class colorama_shim(object):
     def enable(self, enable):
         self._enabled = enable
 
+
 Out_Style = colorama_shim(Colo_Style)
 Out_Fore = colorama_shim(Colo_Fore)
 Err_Style = colorama_shim(Colo_Style)
@@ -173,6 +174,8 @@ def shprint(command, *args, **kwargs):
         msg_width = columns - len(msg_hdr) - 1
         output = command(*args, **kwargs)
         for line in output:
+            if isinstance(line, bytes):
+                line = line.decode('utf-8', errors='replace')
             if logger.level > logging.DEBUG:
                 msg = line.replace(
                     '\n', ' ').replace(