* Added new config attributes: 'SecondsPerBlock','LowPriorityThreshold'
* Added new files:
* Added new method: CompareTo
* Fixed empty Slice case
* Added new methods: LessThan, GreaterThan, Equal, CompareTo
* Added new method: InputIntersection
* Added MaxTransactionSize, GroupOutputByAssetID
* Added ned method: ScriptHash
* Added new method: IsDoubleSpend
* Refactor blockchainer, Added Feer interface, Verify and GetMemPool method
* 1) Added MemPool
2) Added new methods to satisfy the blockchainer interface: IsLowPriority, Verify, GetMemPool
* Added new methods: RelayTxn, RelayDirectly
* Fixed tests
* Implemented RPC server method sendrawtransaction
* Refactor getrawtransaction, sendrawtransaction in separate methods
* Moved 'secondsPerBlock' to config file
* Implemented Kim suggestions:
1) Fixed data race issues
2) refactor Verify method
3) Get rid of unused InputIntersection method due to refactoring Verify method
4) Fixed bug in https://github.com/CityOfZion/neo-go/pull/174#discussion_r264108135
5) minor simplications of the code
* Fixed minor issues related to
1) space
2) getter methods do not need pointer on the receiver
3) error message
4) refactoring CompareTo method in uint256.go
* Fixed small issues
* Use sync.RWMutex instead of sync.Mutex
* Refined (R)Lock/(R)Unlock
* return error instead of bool in Verify methods
* Added utility function GetVarSize
* 1) Added Size method: this implied that Fixed8 implements now the serializable interface. 2) Added few arithmetic operation (Add, Sub, div): this will be used to calculated networkfeeand feePerByte. Changed return value of the Value() method to int instead of int64. Modified fixed8_test accordingly.
* Implemented Size or MarshalJSON method.
- Structs accepting the Size method implement the serializable interface.
- Structs accepting the MarshalJSON method implements the customized json marshaller interface.
* Added fee calculation
* Implemented rcp server method GetRawTransaction
* Updated Tests
* Fixed:
1) NewFixed8 will accept as input int64
2) race condition affecting configDeafault, blockchainDefault
* Simplified Size calculation
* 1) Removed global variable blockchainDefault, configDefault
2) Extended Blockchainer interface to include the methods: References, FeePerByte, SystemFee, NetworkFee
3) Deleted fee_test.go, fee.go. Moved corresponding methods to blockchain_test.go and blockchain.go respectively
4) Amended tx_raw_output.go
* Simplified GetVarSize Method
* Replaced ValueAtAndType with ValueWithType
* Cosmetic changes + Added test case getrawtransaction_7
* Clean up Print statement
* Filled up keys
* Aligned verbose logic with the C#-neo implementation
* Implemented @Kim requests
Refactor server_test.go
* Small fixes
* Fixed verbose logic
Added more tests
Cosmetic changes
* Replaced assert.NoError with require.NoError
* Fixed tests by adding context.Background() as argument
* Fixed tests
