Implemented rpc server method GetRawTransaction (#135)

* 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

pkg/core/blockchainer.go

@@ -1,22 +1,31 @@
 package core
 
 import (
+	"github.com/CityOfZion/neo-go/config"
+	"github.com/CityOfZion/neo-go/pkg/core/transaction"
 	"github.com/CityOfZion/neo-go/pkg/util"
 )
 
 // Blockchainer is an interface that abstract the implementation
 // of the blockchain.
 type Blockchainer interface {
+	GetConfig() config.ProtocolConfiguration
 	AddHeaders(...*Header) error
 	AddBlock(*Block) error
 	BlockHeight() uint32
 	HeaderHeight() uint32
 	GetBlock(hash util.Uint256) (*Block, error)
 	GetHeaderHash(int) util.Uint256
+	GetHeader(hash util.Uint256) (*Header, error)
 	CurrentHeaderHash() util.Uint256
 	CurrentBlockHash() util.Uint256
 	HasBlock(util.Uint256) bool
 	HasTransaction(util.Uint256) bool
 	GetAssetState(util.Uint256) *AssetState
 	GetAccountState(util.Uint160) *AccountState
+	GetTransaction(util.Uint256) (*transaction.Transaction, uint32, error)
+	References(t *transaction.Transaction) map[util.Uint256]*transaction.Output
+	FeePerByte(t *transaction.Transaction) util.Fixed8
+	SystemFee(t *transaction.Transaction) util.Fixed8
+	NetworkFee(t *transaction.Transaction) util.Fixed8
 }