Fixes #405 Adding py3.6 and node 6 & 7 to Travis-CI (#406)
Fixes #405 Adding py3.6 and node 6 & 7 to Travis-CI (#406)

Now testing in Travis-CI for all permutations of Python 2.7, 3.5, & 3.6, and Node 6, 7, & 8.
lektor/lektor,lektor/lektor,lektor/lektor,lektor/lektor