update for flow exports

src/Flux.jl

@@ -1,6 +1,8 @@
 module Flux
 
 using MacroTools, Lazy, Flow, Juno
+import Flow: graphm, syntax, prewalk, iscyclic, Constant, constant, isconstant,
+  value, inputs, thread!, value, inputs
 import Juno: Tree, Row
 
 # Zero Flux Given

src/backend/tensorflow/tensorflow.jl

@@ -1,6 +1,7 @@
 module TF
 
 using ..Flux, Flow, TensorFlow, Juno
+import Flow: Constant, postwalk, value, inputs
 import Flux: accuracy
 import TensorFlow: RawTensor
 import Juno: info