MFC 219886, 226100, 226111, 226341, 242529, 259015, 259016, 259019, 259049,
 259071, 259102, 259110, 259129, 259130, 259178, 259179, 259203, 259221,
 259261, 259532, 259615, 259650, 259651, 259667, 259680, 259727, 259761,
 259772, 259776, 259777, 259830, 259882, 259915, 260160, 260449, 260450,
 260688, 260888, 260953, 261269, 261547, 261551, 261552, 261553, 261585
o Merge vt(4) virtual terminal (a.k.a. newcons) to stable/9.
o Merge teken updates.
o Add few more tty methods required by vt(4).
o Update syscons(4) to work with fresh teken.

Sponsored by:	The FreeBSD Foundation
Bump __FreeBSD_version to reflect presence ov vt(4).

Sponsored by:	The FreeBSD Foundation