Bump version to alpha2.

jeromekelleher · jeromekelleher · commit d5b00d885dbc · 2019-06-14T08:49:53.000+01:00
diff --git a/python/tskit/_version.py b/python/tskit/_version.py
@@ -1,3 +1,3 @@
 # Definitive location for the version number.
 # During development, should be x.y.z.devN
-tskit_version = "0.1.6a1"
+tskit_version = "0.1.6a2"
