Add BIP0023 block proposal fields.

This commit adds the optional block proposal fields defined by BIP0023 to
the GetBlockTemplateResult and TemplateRequest types.

ok @jcvernaleo

jsoncmd.go

@@ -2185,6 +2185,11 @@ type TemplateRequest struct {
 
 	// Basic pool extension from BIP 0023.
 	Target string `json:"target,omitempty"`
+
+	// Block proposal from BIP 0023.  Data is only provided when Mode is
+	// "proposal".
+	Data   string `json:"data,omitempty"`
+	WorkID string `json:"workid,omitempty"`
 }
 
 // isFloatInt64 returns whether the passed float64 is a whole number that safely

jsonresults.go

@@ -118,6 +118,10 @@ type GetBlockTemplateResult struct {
 	MinTime    int64    `json:"mintime,omitempty"`
 	Mutable    []string `json:"mutable,omitempty"`
 	NonceRange string   `json:"noncerange,omitempty"`
+
+	// Block proposal from BIP 0023.
+	Capabilities  []string `json:"capabilities,omitempty"`
+	RejectReasion string   `json:"reject-reason,omitempty"`
 }
 
 // GetNetworkInfoResult models the data returned from the getnetworkinfo command.