[zx] Move public zx headers to match naming convention

The zx library provides headers intended for general use, so the
include path should be spelled <lib/zx/foo.h> as per
https://fuchsia.googlesource.com/docs/+/master/development/languages/c-cpp/naming.md.
This moves the headers into the proper location and updates includes to
match.

Change-Id: I6fc9b2a491b5f8b0d270c4dfc77fa4be5739071b

[ddktl][bti] bti for ethernet

add support for get_bti to ddktl ethernet interface.
Also added for tests and tapdevice.

Change-Id: I826c606d3db15d91ed7c4376ce58fbe86f1352d2

[dev][ethernet] Support multicast filter

Test: /system/test/sys/ethernet-test passes
Multicast filter works with AX88179:
Target-shell-1-$ netdump /dev/class/ethernet/000
(The next command may make "fx shell" fail until reboot)
Target-shell-2-$ ethtool /dev/class/ethernet/000 15 filter \
1.0.94.5.42.88
(within 15 seconds do the next command...)
Host-$ for i in `seq 0 255` ; do timeout 0.01 ping -l 1 -c 1 -Iem1 \
224.5.42.$i ; done
Target shell 1 shows receipt of 1.0.94.5.42.88 (and 3 other addresses).

NET-87 #done

Change-Id: Ideee70c3c74f186784197fc293dc555eefeb843a

[ddktl] Set default for EthmacSetParam to true

Step 3/5

NET-9

Change-Id: Icfc0d2ae2b1bc237f136cb9ccacea83bf39bfe1a

[ddktl] Add EthmacSetParam

Step 1/5

NET-9

Change-Id: I7ff2f20b1a1c743f1a33ae5b6b22119656173b07

[ethernet] Add support for asynchronous eth tx

queue_tx replaces send as the interface for both synchronous and
asynchronous transmissions. Tx data is now passed using ethmac_netbuf_t
structures. If the driver chooses to hold on to the netbuf until
buffer space is available, it can return ZX_ERR_SHOULD_WAIT from queue_tx
and call the ethmac complete_tx() callback when the netbuf is no longer
needed.

NET-212

Change-Id: I2da2c503a12fbea0f8c74d8d1e05b83161a15f4a

[zx] Magenta -> Zircon

The Great Renaming is here!

Change-Id: I3229bdeb2a3d0e40fb4db6fec8ca7d971fbffb94

[zircon][mxtl->fbl] Rename mxtl to fbl

Change-Id: Ie21b6498e1bfb0a7fa0315e40b9e5c3ee78646be

[ethertap] Link status signals

Change-Id: I3b87fe44b4ae17f31a776f1efbc6dcedf4e11890

[dev] Ethertap driver

Allows creation of ethermac devices that read/write to a channel instead
of hardware.

Change-Id: I7455e5a189bf99058f18f0aa5db9e5684e79776f