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/util/fixed8.go

@@ -41,14 +41,19 @@ func (f Fixed8) String() string {
 
 // Value returns the original value representing the Fixed8.
 func (f Fixed8) Value() int64 {
-	return int64(f) / int64(decimals)
+	return int64(f) / decimals
 }
 
-// NewFixed8 return a new Fixed8 type multiplied by decimals.
-func NewFixed8(val int) Fixed8 {
+// NewFixed8 returns a new Fixed8 type multiplied by decimals.
+func NewFixed8(val int64) Fixed8 {
 	return Fixed8(decimals * val)
 }
 
+// NewFixed8FromFloat returns a new Fixed8 type multiplied by decimals.
+func NewFixed8FromFloat(val float64) Fixed8 {
+	return Fixed8(int64(decimals * val))
+}
+
 // Fixed8DecodeString parses s which must be a fixed point number
 // with precision up to 10^-8
 func Fixed8DecodeString(s string) (Fixed8, error) {
@@ -94,7 +99,32 @@ func (f *Fixed8) UnmarshalJSON(data []byte) error {
 	return nil
 }
 
+// Size returns the size in number of bytes of Fixed8.
+func (f *Fixed8) Size() int {
+	return 8
+}
+
 // MarshalJSON implements the json marshaller interface.
 func (f Fixed8) MarshalJSON() ([]byte, error) {
 	return []byte(`"` + f.String() + `"`), nil
 }
+
+// Satoshi defines the value of a 'Satoshi'.
+func Satoshi() Fixed8 {
+	return NewFixed8(1)
+}
+
+// Div implements Fixd8 division operator.
+func (f Fixed8) Div(i int64) Fixed8 {
+	return NewFixed8(f.Value() / i)
+}
+
+// Add implements Fixd8 addition operator.
+func (f Fixed8) Add(g Fixed8) Fixed8 {
+	return NewFixed8(f.Value() + g.Value())
+}
+
+// Sub implements Fixd8 subtraction operator.
+func (f Fixed8) Sub(g Fixed8) Fixed8 {
+	return NewFixed8(f.Value() - g.Value())
+}