Bumping clippy & fixing warnings (#1024)

* Bumping clippy

* Fixing warnings found by clippy

ethcore/src/executive.rs

@@ -26,7 +26,7 @@ use crossbeam;
 
 /// Max depth to avoid stack overflow (when it's reached we start a new thread with VM)
 /// TODO [todr] We probably need some more sophisticated calculations here (limit on my machine 132)
-/// Maybe something like here: https://github.com/ethereum/libethereum/blob/4db169b8504f2b87f7d5a481819cfb959fc65f6c/libethereum/ExtVM.cpp
+/// Maybe something like here: `https://github.com/ethereum/libethereum/blob/4db169b8504f2b87f7d5a481819cfb959fc65f6c/libethereum/ExtVM.cpp`
 const MAX_VM_DEPTH_FOR_THREAD: usize = 64;
 
 /// Returns new address created from address and given nonce.

ethcore/src/trace/bloom.rs

@@ -87,7 +87,7 @@ impl Encodable for BlockTracesBloomGroup {
 	}
 }
 
-/// Represents BloomGroup position in database.
+/// Represents `BloomGroup` position in database.
 #[derive(PartialEq, Eq, Hash, Clone, Debug)]
 pub struct TraceGroupPosition {
 	/// Bloom level.

ethcore/src/trace/db.rs

@@ -33,6 +33,7 @@ use super::flat::{FlatTrace, FlatBlockTraces, FlatTransactionTraces};
 const TRACE_DB_VER: &'static [u8] = b"1.0";
 
 #[derive(Debug, Copy, Clone)]
+#[cfg_attr(feature="dev", allow(enum_variant_names))]
 enum TraceDBIndex {
 	/// Block traces index.
 	BlockTraces = 0,

ethcore/src/trace/mod.rs

@@ -88,7 +88,7 @@ pub trait Tracer: Send {
 	fn traces(self) -> Vec<Trace>;
 }
 
-/// DbExtras provides an interface to query extra data which is not stored in tracesdb,
+/// `DbExtras` provides an interface to query extra data which is not stored in tracesdb,
 /// but necessary to work correctly.
 pub trait DatabaseExtras {
 	/// Returns hash of given block number.