[TF] mylib.tf patch -> strip_right

[tinyfugue at attbi.c. (Galvin)]

This is much faster than the previous:
;==============================================================================
; strip_right()
;
; Strips all trailing spaces from a string.
; USAGE:
; x := strip_right("string")
;
; x        : Returned "string" with no leading spaces.
; "string" : Any string
;==============================================================================
/def strip_right = \
  /let st_=%* %;\
  /RETURN st_