add py36 to envlist

Author: Kully

tox.ini

@@ -37,7 +37,7 @@
 [tox]
 ; The py{A,B,C}-{X,Y} generates a matrix of envs:
 ;   pyA-X,pyA-Y,pyB-X,pyB-Y,pyC-X,pyC-Y
-envlist = py{27,34,35}-{core,optional},py33-core
+envlist = py{27,34,35,36}-{core,optional},py33-core
 
 ; Note that envs can be targeted by deps using the <target>: dep syntax.
 ; Only one dep is allowed per line as of the time of writing. The <target>