codegen: put exception checks inside of a G_UNLIKELY

Fixes bug 730702
glib-2.0: add accessor for GArray's data field

Fixes bug 651505
libsoup-2.4: deprecate Buffer.new and MessageBody.append

These functions require the user to correctly specify a Soup.MemoryUse
argument, but that's easy to get wrong without understanding how the
memory is managed.  Alternatives for these functions which will always
transfer ownership of the memory have been in place since 2.32, so
from now on we will emit a warning when someone tries to use the old
versions.
gstreamer-1.0: update to latest git.

Using bindings some libraries, such as gstreamer-audio-1.0, will break
compatibility with gstreamer 1.0 since gstreamer didn't include
single-include headers until 1.2.
Update GIR-based bindings.
girparser: support return_void metadata argument

This allows us to generate backwards compatible signatures for
functions with a void return value and a single out param for a struct
from metadata files instead of resorting to *-custom.vala.
girparser: improve support for changing symbol types away from instance

This makes it possible to move a symbol from an instance method of one
type to a constructor of another, or to a static method.
girparser: don't deprecate children of deprecated containers

GObject Introspection doesn't support marking entire types as
deprecated, so we end up with a lot of places where the type isn't
deprecated, but every method, property, field, signal, etc. in it is,
which causes a lot of spew during compilation.  This patch allows us
to easily deprecate a type in metadata and any extra deprecation
information on child symbols will be omitted.
json-glib-1.0: update to 1.0.2
gstreamer-1.0: Add gstreamer-allocators-1.0 and gstreamer-riff-1.0
gtkmodule: Error out on malformed signal definition

Connecting to a signal in a gtk composite template needs both the
signal's name and a handler function to connect to.
glib2.0: Mark StaticPrivate as deprecated
girparser: handle multiple identifier-prefixes in namespaces
glib-2.0: add HashTable.get_keys_as_array
glib-2.0: remove HashTable.get_keys_as_array

This was causing a syntax error when trying to compile Vala with an
older version of valac (whatever is in gnome-continuous).  It looks
like we should hold off on adding stuff with this syntax until
next cycle.
gobject: Add Binding.unbind

Fixes bug 730967
xcb: Add more methods and use Vala types for accessing data

https://bugzilla.gnome.org/show_bug.cgi?id=730218
xcb: Add helper methods for GetPropertyReply

Add helper methods for GetPropertyReply so you don't have to access a void
pointer.

https://bugzilla.gnome.org/show_bug.cgi?id=730230
xcb: Replies are nullable and errors are optional

Also a few whitespace consistency changes thrown in.