Add commenting support, badly

This fixes #9, though still suffering from #8.

I'm not particularly happy here though, the edit interface provided lacks context: it simply
is a raw YAML 'body: |' prompt in $EDITOR. Not very friendly.

Unfortunately, the data is just not available to the 'comment' template to put a reference
to the ticket id and summary into place, so I think this requires a PR to go-jira :(

jira-ui.go

@@ -32,6 +32,10 @@ type TicketEditer interface {
 	EditTicket()
 }
 
+type TicketCommenter interface {
+	CommentTicket()
+}
+
 type PagePager interface {
 	NextLine(int)
 	PreviousLine(int)

ticket_list_page.go

@@ -30,6 +30,10 @@ func (p *TicketListPage) EditTicket() {
 	runJiraCmdEdit(p.GetSelectedTicketId())
 }
 
+func (p *TicketListPage) CommentTicket() {
+	runJiraCmdComment(p.GetSelectedTicketId())
+}
+
 func (p *TicketListPage) Create(opts ...interface{}) {
 	ui.Clear()
 	var label string

ticket_show_page.go

@@ -27,6 +27,10 @@ func (p *TicketShowPage) EditTicket() {
 	runJiraCmdEdit(p.TicketId)
 }
 
+func (p *TicketShowPage) CommentTicket() {
+	runJiraCmdComment(p.TicketId)
+}
+
 func (p *TicketShowPage) lastDisplayedLine() int {
 	return lastLineDisplayed(p.uiList, p.firstDisplayLine, 5)
 }

ui_controls.go

@@ -38,6 +38,9 @@ func registerKeyboardHandlers() {
 	ui.Handle("/sys/kbd/E", func(ui.Event) {
 		handleEditKey()
 	})
+	ui.Handle("/sys/kbd/C", func(ui.Event) {
+		handleCommentKey()
+	})
 	ui.Handle("/sys/wnd/resize", func(ui.Event) {
 		handleResize()
 	})
@@ -58,6 +61,12 @@ func handleEditKey() {
 	}
 }
 
+func handleCommentKey() {
+	if obj, ok := currentPage.(TicketCommenter); ok {
+		obj.CommentTicket()
+	}
+}
+
 func handleBackKey() {
 	if obj, ok := currentPage.(GoBacker); ok {
 		obj.GoBack()

utils.go

@@ -34,6 +34,15 @@ func runJiraCmdEdit(ticketId string) {
 	os.Exit(0)
 }
 
+func runJiraCmdComment(ticketId string) {
+	opts := getJiraOpts()
+	c := jira.New(opts)
+	ui.Close()
+	c.CmdComment(ticketId)
+	log.Notice("Regrettably, need to exit after comment. See https://github.com/mikepea/go-jira-ui/issues/8")
+	os.Exit(0)
+}
+
 func runJiraQuery(query string) (interface{}, error) {
 	opts := getJiraOpts()
 	opts["query"] = query