Add -json flag to mirror list|show

Signed-off-by: Joshua Colson <joshua.colson@gmail.com>

deb/remote.go

@@ -52,7 +52,7 @@ type RemoteRepo struct {
 	// Last update date
 	LastDownloadDate time.Time
 	// Checksums for release files
-	ReleaseFiles map[string]utils.ChecksumInfo
+	ReleaseFiles map[string]utils.ChecksumInfo `json:"-"` // exclude from json output
 	// Filter for packages
 	Filter string
 	// Status marks state of repository (being updated, no action)
@@ -71,6 +71,8 @@ type RemoteRepo struct {
 	DownloadUdebs bool
 	// Should we download installer files?
 	DownloadInstaller bool
+	// Packages for json output
+	Packages []string `codec:"-" json:",omitempty"`
 	// "Snapshot" of current list of packages
 	packageRefs *PackageRefList
 	// Parsed archived root