Reverted back to support only version 3.5

Makefile

@@ -60,7 +60,7 @@ test: ## run tests quickly with the default Python
 	py.test
 
 test-all: ## run tests on every Python version with tox
-	tox $(PY_VERSION)
+	tox
 
 coverage: ## check code coverage quickly with the default Python
 	coverage run --source libcryptomarket -m pytest

README.md

@@ -12,7 +12,7 @@ query the data without pain.
 
 ## Prerequisite
 
-Python 3.x and pip.
+Python 3.5+
 
 ## Installation
 

tox.ini

@@ -1,10 +1,8 @@
 [tox]
-envlist = py33, py34, py35, flake8
+envlist = py35, flake8
 
 [travis]
 python =
-    3.3: py33
-    3.4: py34
     3.5: py35
 
 [testenv:flake8]