add manage event to ViewManager
add manage event to ViewManager

Instead of overloading 'activate' with both views and manager and
incongruently using 'deactivate' and 'dismiss' respectively for tear
down, add a new 'manage' event for activation of a child ViewManager.

Note that, for the time being, there is intentionally no
post-transition event (like 'activated' for views) because the
ViewManager's activation isn't animated in any way.

Enyo-DCO-1.1-Signed-off-by: Ryan Duffy (ryan.duffy@lge.com)

PKRoma/enyo,enyojs/enyo,enyojs/enyo,PKRoma/enyo