Correct Google poms to follow central sync requirements

Despite only being relocation poms, it appears that Sonatype requires
that the poms still follow the deployment requirements.

Change-Id: I8471f79dab42239a900a07d81912a3b337c10c6c

Distinct relocation poms and script for gwtproject vs Google

The old script, being already used in Google-managed CI, continues to
deploy poms with com.google groupId. A new script,
maven/push-gwtproject.sh, has the same contents as the old one used to
have, and deploys the org.gwtproject poms.

Samples that use maven have also been updated to use the new ltgt gwt
maven plugin and the new groupIds.

Change-Id: I0f582304faf9546ac37616a78bc7735f8beeba26

Move jsinterop-annotations source code out of GWT.

jsinterop-annotations has its own repo on github. This CL removes
the code from the gwt repo and add a dependency to the jar file
now present in tools repo. The gwt-user.jar distributed in the zip
will still contain these classes, but the maven version will correctly
reference the jar already present in maven central.

Change-Id: I5c341e1ae5ad48ea3bf8104d781b1d16fccdef4a

Deprecate all generated and handmade elemental classes

Change-Id: I1c50c64fb18c8f3b4e9a51cf2434b37a6ded08bd

Revert "Test for 'interactive' readyState during app bootstrap"

This reverts commit f47ba0e.

Reason for revert: Introduces errors in IE9, this event can go off too
soon.

Change-Id: I16256254d3a2e5b88415720fc5dd2ab83335cc56

Supress warning for Array.compare

Change-Id: I60847b035baab185ca93071f8953e4e1fb521319

Allow native classes implement native interfaces with overlays.

Native classes implementing interfaces with overlays triggerred a compiler
error due to the fact that overlays in native intefaces are "default"
methods and that the strategy of implementing them consists in creating
the corresponding synthetic override in classes that don't explicitly
implement the method.

Bug: gwtproject#9440
Bug-Link: gwtproject#9440
Change-Id: I30a100c4d83f13df61fed57a54afb3b25a153250

Allow annotations to be retrieved from binding.

In this patch refactors the annotation access code in JdtUtil and
fixes the issue of retrieving @UnusedCast from a method call
binding.

Change-Id: I2f18a6235b59d96966d20e9e082b5feccc6499e5

Fix incorrect unusable-by-js warning.

@JsFunction interfaces were not completely loaded by UnifyAst
if the functional method was never called. This fact caused that
the interface was not considered as implementable externally, which
in turn confused restriction checker ending in a spurious warning.

Bug: gwtproject#9376
Bug-Link: gwtproject#9376
Change-Id: I92870fde72ab864bc42db8355e283ef3fe17d2ca

Update MobileWebApp sample with Objectify 5.1.13 (from 3.0)

Also update AppEngine SDK to latest version (1.9.40)

Change-Id: If928499d0e18e8112ab61d1a120d9540d9fed451