[virtcon] Read kernel log messages with repeating mode

And for consistency establish a convention of having port_wait_repeating()
handlers return ZX_ERR_NEXT.

Change-Id: I6ae0c879a5fbc373369f77e5c9f7ca0d73f25667

[zx] Magenta -> Zircon

The Great Renaming is here!

Change-Id: I3229bdeb2a3d0e40fb4db6fec8ca7d971fbffb94

[virtcon] Use the non-deprecated mx_timer_set

Since this code isn't setting a repeated timer, mx_timer_start can be
mechanically translated to mx_timer_set.

Change-Id: Ib0fbbcf6df4f7fe53e499fd80163d1bbb978ddcc

[devmgr][mxio][virtcon] fix teardown on devhost crash

If a devhost exits uncleanly, clients waiting on devices may
never find out. Shift mx_device_t from Event to EventPair
so waiters can observe PEER_CLOSED if the devhost blows up.

Also adjust mxio's blocking read/write calls to correctly
return an error in the event of the far side blowing up.

Change-Id: Icecbce5e9b47131a0d6b2e8a60a2fb7813200e24

[virtcon] Use the new MX_OK and MX_ERR_* mx_status_t names

Change-Id: I89dd39bd11d4d4b89321424cfc910b605688e307

[virtcon] cleanup

- remove some unused header includes
- remove unused vcdebug.h (xprintf was not used and now virtcon
filters its own debug prints out of the debug log console so
printf is safe to use if needed)
- clean up rules.mk to better reflect shared sources, libraries
- move shared code from main.cpp to vc-input.cpp
- no longer include main.cpp in virtual-console-test
- remove global lock, no longer needed in new single threaded design

Change-Id: I5aacc0f95f817f25ce96bbfa2f74d4877e9c4a16

[virtcon] eliminate input threads, use ports instead

Change-Id: I35616723c597840400d4155a108829dab5f00793

[virtcon] Keyboard handling: Implement setting the Caps Lock LED

Tell the keyboard to light the LED when Caps Lock is on.

Change-Id: I3e6989b8378f095e1c8274b7dc7d551686215f9c

[gfxconsole][virtcon] move and rename gfxconsole to virtcon

It's no longer a device, it's time for it to leave the
land of devices.

Change-Id: I977c56dbacb0794e6f67daac1dd6e3f4f2632f3d