Add skin to pair_kim neigh-list cutoffs & update docs

doc/src/pair_kim.txt

@@ -47,8 +47,11 @@ section of Section packages"_Section_packages.html#KIM has
 instructions on how to do this with a simple make command, when
 building LAMMPS.
 
-See the examples/kim dir for an input script that uses a KIM model
-(potential) for Lennard-Jones.
+See the examples/kim dir for an input script that uses a KIM model (potential)
+for Lennard-Jones.  Note, for this example input script, the example models
+shipped with with kim-api package must be installed.  See the "Making
+LAMMPS"_Section_start.html#start_3 section and the ./lib/kim/README for details
+on how to build LAMMSPS with the kim-api and how to install the example models.
 
 :line
 

examples/kim/in.kim.lj

@@ -1,4 +1,10 @@
 # 3d Lennard-Jones melt
+#
+# This example requires that the example models provided with
+# the kim-api package are installed.  see the ./lib/kim/README or
+# ./lib/kim/Install.py files for details on how to install these
+# example models.
+#
 
 variable	x index 1
 variable	y index 1

lib/kim/README

@@ -36,14 +36,20 @@ $ ./configure --prefix=${PWD}/../installed-kim-api-vX.Y.Z
 
 $ make
 $ make install
-$ cd ..
 
-4. Remove source and build files
+4. To install the example models shipped with the kim-api
+
+$ cd examples
+$ make model-drivers-all-system
+$ make models-all-system
+$ cd ../..
+
+5. Remove source and build files
 
 $ rm -rf kim-api-vX.Y.Z
 $ rm -rf kim-api-vX.Y.Z.txz
 
-5. To add items do the following (replace the kim item name with your
+6. To add items do the following (replace the kim item name with your
    desired value)
 
 $ source ${PWD}/kim-api-vX.Y.Z/bin/kim-api-vX-activate

src/KIM/pair_kim.cpp

@@ -429,7 +429,8 @@ void PairKIM::init_style()
      neighbor->requests[irequest]->full = 1;
      neighbor->requests[irequest]->ghost = 1;
      neighbor->requests[irequest]->cut = 1;
-     neighbor->requests[irequest]->cutoff = kim_cutoff_values[i];
+     neighbor->requests[irequest]->cutoff
+         = kim_cutoff_values[i] + neighbor->skin;
    }
 
    return;