Bug fix: broadcast `dist_lim` and periodic

Add test of `eddy_graph` with 2 processes.

Bug fix in main program `eddy_graph`: broadcast `dist_lim` and
periodic.

README.md

+This code implements ideas and methods described in the following articles:
+[Chaigneau et al., 2009](https://doi.org/10.1016/j.pocean.2009.07.012)
+[Chaigneau et al., 2011](https://doi.org/10.1029/2011JC007134)
+[Pegliasco et al., 2015](https://doi.org/10.1002/2015jc010950)
+[Laxenaire et al., 2018](https://doi.org/10.1029/2018JC014270)

Tests/short_tests.json

@@ -458,5 +458,15 @@
 	"title" : "Eddy_graph",
 	"input":
 	"&MAIN_NML CORNER_deg = 5.125, -36.375, NLON = 29, NLAT = 17 /\n"
+    },
+    {
+	"commands": [["$src_dir/mkdir_nproc.sh", "2"],
+		     ["mpiexec", "-n", "2", "$build_dir/eddy_graph",
+		      "$src_dir/Tests/Input/Region_1/SHP_triplet_noise"]],
+	"stdout": "eddy_graph_stdout.txt",
+	"title" : "Eddy_graph_2",
+	"description": "Same as Eddy_graph but with 2 processes.",
+	"input":
+	"&MAIN_NML CORNER_deg = 5.125, -36.375, NLON = 29, NLAT = 17 /\n"
     }
 ]

eddy_graph.f90

@@ -98,6 +98,8 @@ program eddy_graph
   call ezmpi_bcast(step, root = 0)
   call ezmpi_bcast(nlon, root = 0)
   call ezmpi_bcast(nlat, root = 0)
+  call ezmpi_bcast(dist_lim, root = 0)
+  call ezmpi_bcast(periodic, root = 0)
   call ezmpi_bcast(copy, root = 0)
   call ezmpi_bcast(n_dates, root = 0)
   if (rank /= 0) allocate(ishape_last(n_dates))