tty_noecho() is used instead of noecho() function or macro.
tty_flush_input() is used instead of flushinp() function or macro.
tty_reset_screen() is used instead of endwin() function or macro.
tty_shutdown() is based on slang_shutdown(). Also implemented for
NCurses as wrapper for endwin().
tty_touch_screen() is used instead of touchwin() function or macro.
tty_set_normal_attrs() is used instead of standend() function or macro.
tty_set_alt_charset() is used instead of acs() and noacs()
functions or macros.
tty_baudrate() is used instead of baudrate() function or macro.
tty_keypad() is used instead of keypad() function or macro.
tty_nodelay() is used instead of nodelay() function or macro.
tty_reset_prog_mode() is used instead of reset_prog_mode() function or macro.
tty_reset_shell_mode() is used instead of reset_shell_mode()
function or macro.
tty_beep() is used instead of beep() function or macro.
src/tty/tty.h:
src/tty/tty-slang.c:
src/tty/tty-ncurses.c: new tty_fill_region() function.
src/dialog.c (widget_erase, dlg_erase): tty_fill_region() function
is applied to erase area of widget and dialog.
Created some TTY functions instead of MC core global variables.
Moved init_layer() function from MC core to TTY layer.
Renamed slang_init() to init_slang().
Added required #include's in TTY layer.
Moved S-Lang color and attribute definitions from src/tty/tty-slang.h
to colors-slang.h.
