Logs limit & log_index bug (#2073)

* Limiting number of logs

* Test for logs

* Fixing logs ordering and indexing

* Fixing sort

* unwrap -> expect

* Revert "unwrap -> expect"

This reverts commit e99e6e77f37692fe568448e768aa72775de8d0cd.

ethcore/src/verification/verification.rs

@@ -241,6 +241,7 @@ mod tests {
 	use spec::*;
 	use transaction::*;
 	use tests::helpers::*;
+	use types::log_entry::{LogEntry, LocalizedLogEntry};
 	use rlp::View;
 
 	fn check_ok(result: Result<(), Error>) {
@@ -333,6 +334,12 @@ mod tests {
 		fn block_receipts(&self, _hash: &H256) -> Option<BlockReceipts> {
 			unimplemented!()
 		}
+
+
+		fn logs<F>(&self, _blocks: Vec<BlockNumber>, _matches: F, _limit: Option<usize>) -> Vec<LocalizedLogEntry>
+			where F: Fn(&LogEntry) -> bool, Self: Sized {
+			unimplemented!()
+		}
 	}
 
 	fn basic_test(bytes: &[u8], engine: &Engine) -> Result<(), Error> {