STYLE: avoid unrestricted dictionary lookup in conversion, sampling, surfMesh

- aids with detection of excess tokens (issue #762)

- deprecated dictionary::operator[] in favour of the lookup() method
  which offers more flexibilty and clarity of purpose.
  Additionally, the read<> and get<> forms should generally be used
  instead anyhow.

src/sampling/sampledSet/array/arraySet.C

@@ -175,8 +175,8 @@ Foam::arraySet::arraySet
 :
     sampledSet(name, mesh, searchEngine, dict),
     coordSys_(dict),
-    pointsDensity_(dict.lookup("pointsDensity")),
-    spanBox_(dict.lookup("spanBox"))
+    pointsDensity_(dict.get<labelVector>("pointsDensity")),
+    spanBox_(dict.get<vector>("spanBox"))
 {
     genSamples();
 }

src/sampling/sampledSet/array/arraySet.H

@@ -47,6 +47,7 @@ SourceFiles
 #define arraySet_H
 
 #include "sampledSet.H"
+#include "labelVector.H"
 #include "DynamicList.H"
 #include "coordinateSystem.H"
 
@@ -73,10 +74,10 @@ class arraySet
         coordinateSystem coordSys_;
 
         //- Point density vector
-        Vector<label> pointsDensity_;
+        labelVector pointsDensity_;
 
         //- Span box
-        Vector<scalar> spanBox_;
+        vector spanBox_;
 
 
     // Private Member Functions