Protocol definitions and daemon for D-Bus at-spi

at-spi allows assistive technologies to access GTK-based applications. Essentially it exposes the internals of applications for automation, so tools such as screen readers, magnifiers, or even scripting interfaces can query and interact with GUI controls. This version of at-spi is a major break from previous versions. It has been completely rewritten to use D-Bus rather than ORBIT / CORBA for its transport protocol.