Bump gocui

... and switch back from stefanhaller's tcell fork to the official tcell. This
basically reverts 7ccb871a45.

vendor/github.com/gdamore/tcell/v2/paste.go

@@ -0,0 +1,48 @@
+// Copyright 2020 The TCell Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use file except in compliance with the License.
+// You may obtain a copy of the license at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package tcell
+
+import (
+	"time"
+)
+
+// EventPaste is used to mark the start and end of a bracketed paste.
+// An event with .Start() true will be sent to mark the start.
+// Then a number of keys will be sent to indicate that the content
+// is pasted in.  At the end, an event with .Start() false will be sent.
+type EventPaste struct {
+	start bool
+	t     time.Time
+}
+
+// When returns the time when this EventPaste was created.
+func (ev *EventPaste) When() time.Time {
+	return ev.t
+}
+
+// Start returns true if this is the start of a paste.
+func (ev *EventPaste) Start() bool {
+	return ev.start
+}
+
+// End returns true if this is the end of a paste.
+func (ev *EventPaste) End() bool {
+	return !ev.start
+}
+
+// NewEventPaste returns a new EventPaste.
+func NewEventPaste(start bool) *EventPaste {
+	return &EventPaste{t: time.Now(), start: start}
+}