finalize json output & add schema (#118)

syft/pkg/package.go

@@ -12,15 +12,15 @@ type ID int64
 
 // Package represents an application or library that has been bundled into a distributable format
 type Package struct {
-	id       ID // this is set when a package is added to the catalog
-	Name     string
-	Version  string
-	FoundBy  string
-	Source   []file.Reference
-	Licenses []string
-	Language Language // TODO: should this support multiple languages as a slice?
-	Type     Type
-	Metadata interface{}
+	id       ID               // this is set when a package is added to the catalog
+	Name     string           `json:"manifest"`
+	Version  string           `json:"version"`
+	FoundBy  string           `json:"found-by"`
+	Source   []file.Reference `json:"sources"`
+	Licenses []string         `json:"licenses"` // TODO: should we move this into metadata?
+	Language Language         `json:"language"` // TODO: should this support multiple languages as a slice?
+	Type     Type             `json:"type"`
+	Metadata interface{}      `json:"metadata,omitempty"`
 }
 
 func (p Package) ID() ID {