Move "symphony" to separate theme package.

themes/symphony/Makefile.am

themes/symphony/README

themes/symphony/bottom-active.png

themes/symphony/bottom-active.xpm

themes/symphony/bottom-inactive.png

themes/symphony/bottom-inactive.xpm

themes/symphony/bottom-left-active.png

themes/symphony/bottom-left-active.xpm

themes/symphony/bottom-left-inactive.png

themes/symphony/bottom-left-inactive.xpm

themes/symphony/bottom-right-active.png

themes/symphony/bottom-right-active.xpm

themes/symphony/bottom-right-inactive.png

themes/symphony/bottom-right-inactive.xpm

themes/symphony/close-active.xpm

themes/symphony/close-inactive.xpm

themes/symphony/close-pressed.xpm

themes/symphony/hide-active.xpm

themes/symphony/hide-inactive.xpm

themes/symphony/hide-pressed.xpm