Drop support for cdecimal (#20)

From https://stackoverflow.com/a/8192918/284318:

> As of Python 3.3, the cdecimal implementation is now the built-in
> implementation of the decimal standard library module, so you don't
> need to install anything. Just use decimal.

Since combining `decimal` and `cdecimal` can result in weird bugs, and
since I will drop Python 2 support in the next release anyways,
supporting `cdecimal` doesn't make sense anymore.

.travis.yml

@@ -12,20 +12,16 @@ env:
     - TOXENV=py27-django16
     - TOXENV=py27-django17
     - TOXENV=py27-django18
-    - TOXENV=py27-django18-cdecimal
 
     - TOXENV=py33-django17
     - TOXENV=py33-django18
-    - TOXENV=py33-django18-cdecimal
 
     - TOXENV=py34-django15
     - TOXENV=py34-django16
     - TOXENV=py34-django17
     - TOXENV=py34-django18
-    - TOXENV=py34-django18-cdecimal
 
     - TOXENV=py35-django18
-    - TOXENV=py35-django18-cdecimal
 
     - TOXENV=pypy-django14
     - TOXENV=pypy-django15

README.rst

@@ -25,12 +25,8 @@ Django ticket `#361 <https://code.djangoproject.com/ticket/361>`_ has been
 closed as *wontfix*, so I had to create an alternative that is easy to install
 in a new Django project.
 
-It currently supports ``int``, ``float``, ``Decimal`` and ``cDecimal`` types, or
-any other type that can be converted to int or float.
-
-**WARNING: Note that when you have the ``cdecimal`` package installed, I assume
-all ``Decimal`` values that are passed to the tag are of ``cdecimal`` type. If
-they aren't, weird things may happen.**
+It currently supports ``int``, ``float`` and ``Decimal`` types, or any other
+type that can be converted to int or float.
 
 
 Installation

mathfilters/templatetags/mathfilters.py

@@ -2,10 +2,7 @@
 from __future__ import print_function, division, absolute_import, unicode_literals
 
 import logging
-try:
-    from cdecimal import Decimal
-except ImportError:
-    from decimal import Decimal
+from decimal import Decimal
 
 from django.template import Library
 

mathfilters/tests.py

@@ -3,10 +3,7 @@
 
 import unittest
 import logging
-try:
-    from cdecimal import Decimal
-except ImportError:
-    from decimal import Decimal
+from decimal import Decimal
 
 from templatetags import mathfilters
 

tox.ini

@@ -2,10 +2,10 @@
 [tox]
 envlist =
     py26-django11, py26-django12, py26-django13, py26-django14, py26-django15, py26-django16,
-    py27-django14, py27-django15, py27-django16, py27-django17, py27-django18, py27-django18-cdecimal,
-    py33-django17, py33-django18, py33-django18-cdecimal,
-    py34-django15, py34-django16, py34-django17, py34-django18, py34-django18-cdecimal,
-    py35-django18, py35-django18-cdecimal,
+    py27-django14, py27-django15, py27-django16, py27-django17, py27-django18,
+    py33-django17, py33-django18,
+    py34-django15, py34-django16, py34-django17, py34-django18,
+    py35-django18,
     pypy-django14, pypy-django15, pypy-django16, pypy-django17, pypy-django18,
     pypy3-django17, pypy3-django18
 
@@ -77,12 +77,6 @@ basepython=python2.7
 deps=
     django<1.9
 
-[testenv:py27-django18-cdecimal]
-basepython=python2.7
-deps=
-    django<1.9
-    http://www.bytereef.org/software/mpdecimal/releases/cdecimal-2.3.tar.gz
-
 # Python 3.3
 
 [testenv:py33-django17]
@@ -95,12 +89,6 @@ basepython=python3.3
 deps=
     django<1.9
 
-[testenv:py33-django18-cdecimal]
-basepython=python3.3
-deps=
-    django<1.9
-    http://www.bytereef.org/software/mpdecimal/releases/cdecimal-2.3.tar.gz
-
 # Python 3.4
 
 [testenv:py34-django15]
@@ -123,25 +111,13 @@ basepython=python3.4
 deps=
     django<1.9
 
-[testenv:py34-django18-cdecimal]
-basepython=python3.4
-deps=
-    django<1.9
-    http://www.bytereef.org/software/mpdecimal/releases/cdecimal-2.3.tar.gz
-
 # Python 3.5
 
 [testenv:py35-django18]
 basepython=python3.5
 deps=
     django<1.9
 
-[testenv:py35-django18-cdecimal]
-basepython=python3.5
-deps=
-    django<1.9
-    http://www.bytereef.org/software/mpdecimal/releases/cdecimal-2.3.tar.gz
-
 # Pypy
 
 [testenv:pypy-django14]