Reintegrate merge from wsjtx_exp branch.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6122 ab8295b8-cf94-4d9e-aec4-7959e3be5d79

lib/shell.f90

@@ -0,0 +1,27 @@
+subroutine shell(n,a)
+  integer n
+  real a(n)
+  integer i,j,inc
+  real v
+
+  inc=1
+1 inc=3*inc+1
+  if(inc.le.n) go to 1
+2  inc=inc/3
+
+  do i=inc+1,n
+     v=a(i)
+     j=i
+3    if(a(j-inc).gt.v) then
+        a(j)=a(j-inc)
+        j=j-inc
+        if(j.le.inc) go to 4
+        go to 3
+     endif
+4    a(j)=v
+  enddo
+
+  if(inc.gt.1) go to 2
+
+  return
+end subroutine shell