Minimal parachain framework part 1 (#113)

* dynamic inclusion threshold calculator

* collators interface

* collation helpers

* initial proposal-creation future

* create proposer when asked to propose

* remove local_availability duty

* statement table tracks includable parachain count

* beginnings of timing future

* finish proposal logic

* remove stray println

* extract shared table to separate module

* change ordering

* includability tracking

* fix doc

* initial changes to parachains module

* initialise dummy block before API calls

* give polkadot control over round proposer based on random seed

* propose only after enough candidates

* flesh out parachains module a bit more

* set_heads

* actually introduce set_heads to runtime

* update block_builder to accept parachains

* split block validity errors from real errors in evaluation

* update WASM runtimes

* polkadot-api methods for parachains additions

* delay evaluation until candidates are ready

* comments

* fix dynamic inclusion with zero initial

* test for includability tracker

* wasm validation of parachain candidates

* move primitives to primitives crate

* remove runtime-std dependency from codec

* adjust doc

* polkadot-parachain-primitives

* kill legacy polkadot-validator crate

* basic-add test chain

* test for basic_add parachain

* move to test-chains dir

* use wasm-build

* new wasm directory layout

* reorganize a bit more

* Fix for rh-minimal-parachain (#141)

* Remove extern "C"

We already encountered such behavior (bug?) in pwasm-std, I believe.

* Fix `panic_fmt` signature by adding `_col`

Wrong `panic_fmt` signature can inhibit some optimizations in LTO mode.

* Add linker flags and use wasm-gc in build script

Pass --import-memory to LLD to emit wasm binary with imported memory.

Also use wasm-gc instead of wasm-build.

* Fix effective_max.

I'm not sure why it was the way it was actually.

* Recompile wasm.

* Fix indent

* more basic_add tests

* validate parachain WASM

* produce statements on receiving statements

* tests for reactive statement production

* fix build

* add OOM lang item to runtime-io

* use dynamic_inclusion when evaluating as well

* fix update_includable_count

* remove dead code

* grumbles

* actually defer round_proposer logic

* update wasm

* address a few more grumbles

* grumbles

* update WASM checkins

* remove dependency on tokio-timer

substrate/polkadot/consensus/src/error.rs

@@ -16,45 +16,30 @@
 
 //! Errors that can occur during the consensus process.
 
-use primitives::block::{HeaderHash, Number};
+use polkadot_primitives::AccountId;
+
 error_chain! {
 	links {
 		PolkadotApi(::polkadot_api::Error, ::polkadot_api::ErrorKind);
 		Bft(::bft::Error, ::bft::ErrorKind);
 	}
 
-	foreign_links {
-		Io(::std::io::Error);
-		SharedIo(::futures::future::SharedError<::std::io::Error>);
-	}
-
 	errors {
 		InvalidDutyRosterLength(expected: usize, got: usize) {
 			description("Duty Roster had invalid length"),
 			display("Invalid duty roster length: expected {}, got {}", expected, got),
 		}
-		ProposalNotForPolkadot {
-			description("Proposal provided not a Polkadot block."),
-			display("Proposal provided not a Polkadot block."),
+		NotValidator(id: AccountId) {
+			description("Local account ID not a validator at this block."),
+			display("Local account ID ({:?}) not a validator at this block.", id),
 		}
-		TimestampInFuture {
-			description("Proposal had timestamp too far in the future."),
-			display("Proposal had timestamp too far in the future."),
+		PrematureDestruction {
+			description("Proposer destroyed before finishing proposing or evaluating"),
+			display("Proposer destroyed before finishing proposing or evaluating"),
 		}
-		WrongParentHash(expected: HeaderHash, got: HeaderHash) {
-			description("Proposal had wrong parent hash."),
-			display("Proposal had wrong parent hash. Expected {:?}, got {:?}", expected, got),
-		}
-		WrongNumber(expected: Number, got: Number) {
-			description("Proposal had wrong number."),
-			display("Proposal had wrong number. Expected {:?}, got {:?}", expected, got),
-		}
-		ProposalTooLarge(size: usize) {
-			description("Proposal exceeded the maximum size."),
-			display(
-				"Proposal exceeded the maximum size of {} by {} bytes.",
-				::MAX_TRANSACTIONS_SIZE, ::MAX_TRANSACTIONS_SIZE.saturating_sub(*size)
-			),
+		Timer(e: String) {
+			description("Failed to register or resolve async timer."),
+			display("Timer failed: {}", e),
 		}
 		Executor(e: ::futures::future::ExecuteErrorKind) {
 			description("Unable to dispatch agreement future"),