Remove the ISO 14755 feature

And move it to the patches section.
Keeping it would force to add an exec pledge on OpenBSD, and some
people think it's bloated, so bye!

st.h

@@ -80,7 +80,6 @@ void die(const char *, ...);
 void redraw(void);
 void draw(void);
 
-void iso14755(const Arg *);
 void printscreen(const Arg *);
 void printsel(const Arg *);
 void sendbreak(const Arg *);