Make decl_event! more ergonomic (#723)

* Improve and simplify `decl_event!`

- RawEvent is not required anymore to be written in the defintion
- Events with and without parameters are now supported everywhere

* Make `decl_event!` more flexible with the automatic naming of generic parameters

The macro will now automatically derive the name of a generic parameter
from the trait type name, if no explicit name is given.

`where Balance = <T as Trait>::Balance` can be simplified to
`where <T as Trait>::Balance`.

* Adapts to latest refactoring changes

substrate/srml/council/src/motions.rs

@@ -49,9 +49,7 @@ pub enum Origin {
 
 /// Event for this module.
 decl_event!(
-	pub enum Event<T> with RawEvent<Hash, AccountId>
-		where <T as system::Trait>::Hash, <T as system::Trait>::AccountId
-	{
+	pub enum Event<T> where <T as system::Trait>::Hash, <T as system::Trait>::AccountId {
 		/// A motion (given hash) has been proposed (by given account) with a threshold (given u32).
 		Proposed(AccountId, ProposalIndex, Hash, u32),
 		/// A motion (given hash) has been voted on by given account, leaving

substrate/srml/council/src/seats.rs

@@ -156,9 +156,7 @@ decl_storage! {
 
 decl_event!(
 	/// An event in this module.
-	pub enum Event<T> with RawEvent<AccountId>
-		where <T as system::Trait>::AccountId
-	{
+	pub enum Event<T> where <T as system::Trait>::AccountId {
 		/// reaped voter, reaper
 		VoterReaped(AccountId, AccountId),
 		/// slashed reaper

substrate/srml/council/src/voting.rs

@@ -55,9 +55,7 @@ decl_storage! {
 
 /// An event in this module.
 decl_event!(
-	pub enum Event<T> with RawEvent<Hash>
-		where <T as system::Trait>::Hash
-	{
+	pub enum Event<T> where <T as system::Trait>::Hash {
 		/// A voting tally has happened for a referendum cancelation vote.
 		/// Last three are yes, no, abstain counts.
 		TallyCancelation(Hash, u32, u32, u32),