Remove implicit relative imports

src/sage/coding/source_coding/huffman.py

@@ -27,12 +27,12 @@
 #
 # http://www.gnu.org/licenses/
 ###########################################################################
-from __future__ import print_function
+from __future__ import print_function, absolute_import
 
 from heapq import heapify, heappush, heappop
 
-from prefix_coding import PrefixCoding
-from misc import SimpleTable
+from .prefix_coding import PrefixCoding
+from .misc import SimpleTable
 
 class Huffman(PrefixCoding):
     r"""

src/sage/coding/source_coding/prefix_coding.py

@@ -18,6 +18,7 @@
 # (at your option) any later version.
 #                  http://www.gnu.org/licenses/
 #*****************************************************************************
+from __future__ import absolute_import
 
 from abc import ABCMeta, abstractmethod
 from itertools import product
@@ -26,7 +27,7 @@
 
 from sage.structure.sage_object import SageObject
 from sage.graphs.digraph import DiGraph
-from misc import frequency_table
+from .misc import frequency_table
 
 # Key for code length of the longest code in a decoding table.
 MAX_KEY_LEN = "key_len"

src/sage/coding/source_coding/shannon.py

@@ -19,13 +19,13 @@
 # (at your option) any later version.
 #                  http://www.gnu.org/licenses/
 #*****************************************************************************
-from __future__ import print_function
+from __future__ import print_function, absolute_import
 
 from math import ceil, log
 from operator import itemgetter
 
-from prefix_coding import PrefixCoding 
-from misc import SimpleTable, first_binary_dec_places
+from .prefix_coding import PrefixCoding 
+from .misc import SimpleTable, first_binary_dec_places
 
 class Shannon(PrefixCoding):
     r"""

src/sage/coding/source_coding/shannon_fano.py

@@ -19,12 +19,12 @@
 # (at your option) any later version.
 #                  http://www.gnu.org/licenses/
 #*****************************************************************************
-from __future__ import print_function
+from __future__ import print_function, absolute_import
 
 from operator import itemgetter
 
-from prefix_coding import PrefixCoding
-from misc import SimpleTable
+from .prefix_coding import PrefixCoding
+from .misc import SimpleTable
 
 class ShannonFano(PrefixCoding):
     r"""

src/sage/coding/source_coding/shannon_fano_elias.py

@@ -19,14 +19,14 @@
 # (at your option) any later version.
 #                  http://www.gnu.org/licenses/
 #*****************************************************************************
-from __future__ import print_function
+from __future__ import print_function, absolute_import
 
 from math import ceil, log
 
 from six import iteritems
 
-from prefix_coding import PrefixCoding
-from misc import SimpleTable, first_binary_dec_places
+from .prefix_coding import PrefixCoding
+from .misc import SimpleTable, first_binary_dec_places
 
 class ShannonFanoElias(PrefixCoding):
     r"""