Function: strjoin
Section: programming/specific
C-Name: strjoin
Prototype: GDG
Help: strjoin(v,{p = ""}): joins the strings in vector v, separating them with
 delimiter p.
Doc: joins the strings in vector $v$, separating them with delimiter $p$.
 The reverse operation is \kbd{strsplit}.
 \bprog
 ? v = ["abc", "def", "ghi"]
 ? strjoin(v, "/")
 %2 = "abc/def/ghi"
 ? strjoin(v)
 %3 = "abcdefghi"
 @eprog
