af-binder: Upgrade

af-binder: Upgrade

This upgrade of the binder includes improvement in
event handling (SPEC-3069) and minor fixes.
Unscription should now be immediately effective
as expected, no matter how many subscribe was done.

Included commits:
 * 8828c6be main-afb-client-demo: Fix typo
 * f3d1f19a afb-apiset: Fix start of apis
 * 18d28239 AFB.js: pass event name
 * ca0f859d afb-proto-ws: Improve comment and names
 * f40979c7 afb-proto-ws: Add message for unexpected event
 * c6fcbec3 afb-evt: Improve name of listening functions
 * 36ed9d2e afb-evt: Ensure unsubscribe works
 * 164f1414 afb-ws-client: Improve direct URI
 * 65353dce Update copyright dates

Bug-AGL: SPEC-3066
Bug-AGL: SPEC-3069
Bug-AGL: SPEC-3087
Bug-AGL: SPEC-3094

Change-Id: I499643564a1026f54b7cfd68f73352561e1d8649
Signed-off-by: Jose Bollo <jose.bollo@iot.bzh>