Collator node workflow (#280)

* arbitrary application logic in CLI

* collation work

* split up exit and work futures in application

* collation node workflow

* typo

* indentation fix

* doc grumbles

* rename Application to Worker

* refactor Worker::exit to exit_only

substrate/Cargo.lock

@@ -1374,7 +1374,9 @@ dependencies = [
 name = "polkadot"
 version = "0.2.0"
 dependencies = [
+ "ctrlc 1.1.1 (git+https://github.com/paritytech/rust-ctrlc.git)",
  "error-chain 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
  "polkadot-cli 0.2.0",
 ]
 
@@ -1405,7 +1407,6 @@ dependencies = [
  "app_dirs 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "atty 0.2.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "clap 2.32.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "ctrlc 1.1.1 (git+https://github.com/paritytech/rust-ctrlc.git)",
  "ed25519 0.1.0",
  "env_logger 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "error-chain 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1441,10 +1442,14 @@ dependencies = [
 name = "polkadot-collator"
 version = "0.1.0"
 dependencies = [
+ "ed25519 0.1.0",
  "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
- "polkadot-parachain 0.1.0",
+ "log 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "polkadot-api 0.1.0",
+ "polkadot-cli 0.2.0",
  "polkadot-primitives 0.1.0",
  "polkadot-runtime 0.1.0",
+ "substrate-client 0.1.0",
  "substrate-codec 0.1.0",
  "substrate-primitives 0.1.0",
 ]
@@ -1460,7 +1465,6 @@ dependencies = [
  "log 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "polkadot-api 0.1.0",
- "polkadot-collator 0.1.0",
  "polkadot-parachain 0.1.0",
  "polkadot-primitives 0.1.0",
  "polkadot-runtime 0.1.0",