window: Export is_title_onscreen and shove_title_onscreen as well

This was fixed in the master version of the commit, but I forgot to
squash it on the Wayland branch.
common: remove documentation for dead grab ops
window: Remove transient_for_as_xid

It's unused, and it exposes an X11-specific property to API.
window: Make window_is_terminal private
stack: Flatten and simplify the default focus window logic
Start hacking out use of xtransient_for

It won't work under Wayland.
window: Move meta_window_configure_notify to window-x11
window: Remove bogus comment

These fields haven't been around for quite some time.
window: Remove another bogus comment

It's not referring to anything!
window: Remove vfunc slots for signals

These aren't used currently, and we're going to be adding
more vfuncs.
window: Remove meta_window_is_modal

It relies on EWMH concepts. Wayland simply has a MODAL_DIALOG type.
Replace wm_state_modal usage with META_WINDOW_TYPE_DIALOG
window: Remove meta_window_set_gravity as "public" API
window: Remove an unused bit
Update .gitignore
wayland-keyboard: Don't use our own tracking to detect autorepeat

Clutter already marks all autorepeat key events it as synthetic
key events. We can simply ignore these instead of relying on custom
key tracking code.
wayland-keyboard: Make sure we send an updated modifiers event

Any given clutter event carries the modifier state as it was before it
occured but, for the wayland modifiers event, we want the state
including the current event.

To fix this, we'll keep our xkb_state instance around instead of the
serialized mods.

https://bugzilla.gnome.org/show_bug.cgi?id=722847
wayland-keyboard: Split out a function to determine the evdev keycode

We will need to use this is in another place on the next commit.

https://bugzilla.gnome.org/show_bug.cgi?id=722847
wayland: Update keyboard state unconditionally

In particular we need to know about all key events to keep the xkb
state reliable even if the event is then consumed by a global shortcut
or grab and never reaches any wayland client.

We also need to keep track of all pressed keys at all times so that we
can send an updated set or pressed keys to the focused client when a
grab ends.

https://bugzilla.gnome.org/show_bug.cgi?id=722847
window: Split out recalc of skip_taskbar / skip_pager

This will be our first attempt for the MetaWindowX11Private