Add classes Fl_SVG_File_Surface and Fl_EPS_File_Surface to draw to SVG and EPS.

Test programs device and pixmap_browser use these new classes.
Class Fl_SVG_File_Surface can be optionally made non functional using the
--disable-svg configure option or turning off OPTION_USE_SVG in CMake.
Class Fl_EPS_File_Surface can be optionally made non functional using the
--disable-print configure option or turning off OPTION_PRINT_SUPPORT in CMake.