curses splash/copyright screen, role prompt

Back out '#include "date.h"' so that cursinit.c won't be recompiled
every time any other file(s) need to be compiled.  It doesn't need
patchlevel.h either.  There is already a straightforward way to fetch
the copyright banner lines from version.c.

The splash screen (ascii art spelling "NetHack" preceding the normal
copyright lines) was invisible when showing white text on white-ish
background.  Make it honor !guicolor.

"Shall I pick a character's role, race, gender and alignment for you?
 [ynaq] (y) " was too wide to accept the answer on the same line on
an 80-column display so "(y) " was placed on the second line.  That's
constructed in the core; change the construction to omit " a" when
using "character" rather than a role name.  (tty shortens it by omitting
the default " (y)"; with " a" gone, it could revert to normal prompt.)

Also a bit of lint cleanup and some reformatting of cursinit.c....

win/curses/cursinvt.c

@@ -16,9 +16,7 @@ curses_update_inv(void)
 {
     WINDOW *win = curses_get_nhwin(INV_WIN);
     boolean border;
-    int x = 0;
-    int y = 0;
-    attr_t attr = A_UNDERLINE;
+    int x = 0, y = 0;
 
     /* Check if the inventory window is enabled in first place */
     if (!win) {