Bump gocui

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

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

@@ -0,0 +1,73 @@
+// Copyright 2015 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 (
+	"errors"
+	"time"
+
+	"github.com/gdamore/tcell/v2/terminfo"
+)
+
+var (
+	// ErrTermNotFound indicates that a suitable terminal entry could
+	// not be found.  This can result from either not having TERM set,
+	// or from the TERM failing to support certain minimal functionality,
+	// in particular absolute cursor addressability (the cup capability)
+	// is required.  For example, legacy "adm3" lacks this capability,
+	// whereas the slightly newer "adm3a" supports it.  This failure
+	// occurs most often with "dumb".
+	ErrTermNotFound = terminfo.ErrTermNotFound
+
+	// ErrNoScreen indicates that no suitable screen could be found.
+	// This may result from attempting to run on a platform where there
+	// is no support for either termios or console I/O (such as nacl),
+	// or from running in an environment where there is no access to
+	// a suitable console/terminal device.  (For example, running on
+	// without a controlling TTY or with no /dev/tty on POSIX platforms.)
+	ErrNoScreen = errors.New("no suitable screen available")
+
+	// ErrNoCharset indicates that the locale environment the
+	// program is not supported by the program, because no suitable
+	// encoding was found for it.  This problem never occurs if
+	// the environment is UTF-8 or UTF-16.
+	ErrNoCharset = errors.New("character set not supported")
+
+	// ErrEventQFull indicates that the event queue is full, and
+	// cannot accept more events.
+	ErrEventQFull = errors.New("event queue full")
+)
+
+// An EventError is an event representing some sort of error, and carries
+// an error payload.
+type EventError struct {
+	t   time.Time
+	err error
+}
+
+// When returns the time when the event was created.
+func (ev *EventError) When() time.Time {
+	return ev.t
+}
+
+// Error implements the error.
+func (ev *EventError) Error() string {
+	return ev.err.Error()
+}
+
+// NewEventError creates an ErrorEvent with the given error payload.
+func NewEventError(err error) *EventError {
+	return &EventError{t: time.Now(), err: err}
+}