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/test-runtime/wasm/Cargo.lock

@@ -1087,6 +1087,19 @@ dependencies = [
  "substrate-trie 0.4.0",
 ]
 
+[[package]]
+name = "substrate-consensus-aura-primitives"
+version = "0.1.0"
+dependencies = [
+ "parity-codec 2.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-io 0.1.0",
+ "sr-primitives 0.1.0",
+ "sr-version 0.1.0",
+ "srml-support 0.1.0",
+ "substrate-client 0.1.0",
+ "substrate-primitives 0.1.0",
+]
+
 [[package]]
 name = "substrate-consensus-common"
 version = "0.1.0"
@@ -1208,6 +1221,7 @@ dependencies = [
  "sr-version 0.1.0",
  "srml-support 0.1.0",
  "substrate-client 0.1.0",
+ "substrate-consensus-aura-primitives 0.1.0",
  "substrate-primitives 0.1.0",
 ]