Instead of reading the terminal size on every status update, register
for SIGWINCH to read and store the size when it changes.
This reapplies I555ad21a31a2c924ab0ca681e0c8f00df42a370a with a fix
for a race condition in TestSmartStatusOutputWidthChange.
Test: status_test.go
Change-Id: If342cb4cc8e4ed57af9e3bb417758348c9c41247
Instead of reading the terminal size on every status update, register
for SIGWINCH to read and store the size when it changes.
Test: status_test.go
Change-Id: I555ad21a31a2c924ab0ca681e0c8f00df42a370a
Bolding the status line provides differentiation between output
of each command.
Test: status_test.go
Change-Id: I9d46761e69c5af0a0aa86c7921e121cfd2a3fc82
terminal.Writer is now just a wrapper around stdio.Stdout() without
any useful functionality. Replace it with stdio.Stdout() as an
io.Writer.
Test: ui/terminal/status_test.go
Change-Id: I5bc5476afdca950b505642f0135a3af9d37fbe24
