library: re-arrange escape commands

escaped_copy(): only appears in ps, moved to ps/output.c
escape_strlist() only used in escape.c made static
escape_command() used in library, made internal
procps.h no longer includes escape.h

escape_str() used by library and ps so needs to be exported
definition put into procps.h including the odd define required.
Far from ideal to have it this way, will look at it another time
to have it all in, all out or split nicer so its not in the API;
perhaps a lib/ file?

proc/procps.h

@@ -20,7 +20,6 @@
 
 /* includes that show public exports go here */
 #include <proc/diskstat.h>
-#include <proc/escape.h>
 #include <proc/meminfo.h>
 #include <proc/namespace.h>
 #include <proc/pids.h>
@@ -31,4 +30,8 @@
 #include <proc/vmstat.h>
 #include <proc/uptime.h>
 
+// FIXME: only public function in escape.c
+#define ESC_STRETCH 1  // since we mangle to '?' this is 1 (would be 4 for octal escapes)
+int escape_str(char *__restrict dst, const char *__restrict src, int bufsize, int *maxcells);
+
 #endif