Add Glib::Threads::* in threads.h, deprecating everything in thread.h

	* glib/src/filelist.am:
	* glib/src/thread.[hg|ccg]: Deprecate the whole file, adding
	deprecation doxygen comments to all API.
	* glib/src/threads.[hg|ccg]: A new Threads namespace containing
	equivalents for everything in thread.h, implemented using
	only non-deprecated glib API. This was necessary because we had
	to break the ABI to do this.
	* glib/glibmm.h: Include threads.h

	* glib/glibmm/main.[h|cc]: Added a wait() method overload that
	takes the new types, deprecating the existing wait() method.

	* examples/network/resolver.cc:
	* examples/network/socket-client.cc:
	* examples/network/socket-server.cc:
	* examples/thread/dispatcher.cc:
	* examples/thread/dispatcher2.cc:
	* examples/thread/thread.cc:
	* examples/thread/threadpool.cc:
	* glib/glibmm/dispatcher.cc:
	* glib/glibmm/exceptionhandler.cc:
	* glib/glibmm/threadpool.[h|cc]: Use the new Glib::Threads::* types
	instead of thread.h.