Remove Python2 support

Author: petertodd

README.md

@@ -1,6 +1,6 @@
 # python-bitcoinlib
 
-This Python2/3 library provides an easy interface to the bitcoin data
+This Python3 library provides an easy interface to the bitcoin data
 structures and protocol. The approach is low-level and "ground up", with a
 focus on providing tools to manipulate the internals of how Bitcoin works.
 
@@ -95,9 +95,7 @@ the Satoshi codebase.
 
 Under bitcoin/tests using test data from Bitcoin Core. To run them:
 
-    python -m unittest discover && python3 -m unittest discover
-
-Please run the tests on both Python2 and Python3 for your pull-reqs!
+    python3 -m unittest discover
 
 Alternately, if Tox (see https://tox.readthedocs.org/) is available on your
 system, you can run unit tests for multiple Python versions:
@@ -107,11 +105,9 @@ system, you can run unit tests for multiple Python versions:
 Currently, the following implementations are tried (any not installed are
 skipped):
 
-    * CPython 2.7
     * CPython 3.3
     * CPython 3.4
     * CPython 3.5
-    * PyPy
     * PyPy3
 
 HTML coverage reports can then be found in the htmlcov/ subdirectory.

bitcoin/rpc.py

@@ -42,13 +42,6 @@
 except ImportError:
     import urlparse
 
-# needed for python2 compatibility
-if sys.version < '3':
-    try:
-        FileNotFoundError
-    except NameError:
-        FileNotFoundError = IOError
-
 import bitcoin
 from bitcoin.core import COIN, x, lx, b2lx, CBlock, CBlockHeader, CTransaction, COutPoint, CTxOut
 from bitcoin.core.script import CScript

tox.ini

@@ -2,7 +2,7 @@
 
 [tox] #-------------------------------------------------------------------
 
-envlist = reset,py27,py33,py34,py35,pypy,pypy3,stats
+envlist = reset,py33,py34,py35,pypy3,stats
 skip_missing_interpreters = True
 
 [testenv] #---------------------------------------------------------------