Punish offline validators, aura-style (#1216)

* make offline-reporting infrastructure more generic

* add a listener-trait for watching when the timestamp has been set

* prevent inclusion of empty offline reports

* add test for exclusion

* generate aura-offline reports

* ability to slash many times for being offline "multiple" times

* Logic for punishing validators for missing aura steps

* stub tests

* pave way for verification of timestamp vs slot

* alter aura import queue to wait for timestamp

* check timestamp matches seal

* do inherent check properly

* service compiles

* all tests compile

* test srml-aura logic

* aura tests pass

* everything builds

* some more final tweaks to block authorship for aura

* switch to manual delays before step

* restore substrate-consensus-aura to always std and address grumbles

* update some state roots in executor tests

* node-executor tests pass

* get most tests passing

* address grumbles

substrate/core/consensus/aura/primitives/Cargo.toml

@@ -0,0 +1,26 @@
+[package]
+name = "substrate-consensus-aura-primitives"
+version = "0.1.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+description = "Primitives for Aura consensus"
+
+[dependencies]
+parity-codec = { version = "2.1", default-features = false }
+substrate-client = { path = "../../../client", default-features = false }
+substrate-primitives = { path = "../../../primitives", default-features = false }
+srml-support = { path = "../../../../srml/support", default-features = false }
+sr-primitives = { path = "../../../sr-primitives", default-features = false }
+sr-version = { path = "../../../sr-version", default-features = false }
+sr-io = { path = "../../../sr-io", default-features = false }
+
+[features]
+default = ["std"]
+std = [
+	"parity-codec/std",
+	"substrate-client/std",
+	"substrate-primitives/std",
+	"srml-support/std",
+	"sr-primitives/std",
+	"sr-version/std",
+	"sr-io/std",
+]