Restructured tones_dir, added tones_dir to interface.conf

Restructured tones_dir, added tones_dir to interface.conf
Code cleanup..

	modified:   README
	modified:   apppbx.cpp
	modified:   default/interface.conf
	modified:   default/options.conf
	modified:   dss1.cpp
	modified:   extension.c
	modified:   gsm.cpp
	modified:   interface.c
	modified:   interface.h
	modified:   mISDN.cpp
	modified:   options.c
	modified:   options.h
	modified:   port.cpp