* gimp/app/tools/Makefile.am
	* gimp/app/tools/gimp-tools.c
	* gimp/app/tools/gimpalignoptions.c
	* gimp/app/tools/gimpalignoptions.h
	* gimp/app/tools/gimpaligntool.c
	* gimp/app/tools/gimpaligntool.h: Add new tool for
	aligning layers etc, as described in bug #147437.

	* gimp/app/core/gimpitem.c
	* gimp/app/core/gimpitem.h (gimp_item_align): add
	function required by new tool.

	* gimp/app/core/core-enums.c
	* gimp/app/core/core-enums.h: add enum for alignment
	types.

	* gimp/themes/Default/images/stock-hcenter-24.png
	* gimp/themes/Default/images/stock-vcenter-24.png
	* gimp/libgimpwidgets/gimpstock.c
	* gimp/libgimpwidgets/gimpstock.h
	* gimp/themes/Default/images/Makefile.am
	* gimp/themes/Default/images/makefile.msc: add two
	stock symbols, modeled on the gravity symbols.