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.

applications/utilities/mesh/conversion/ccm/foamToCcm/getTimeIndex.H

@@ -21,23 +21,8 @@
 
         if (io.typeHeaderOk<IOdictionary>(true))
         {
-            IOdictionary timeObject
-            (
-                IOobject
-                (
-                    "time",
-                    runTime.timeName(),
-                    "uniform",
-                    runTime,
-                    IOobject::MUST_READ,
-                    IOobject::NO_WRITE,
-                    false
-                )
-            );
-
-            label index;
-            timeObject.lookup("index") >> index;
-            timeName = Foam::name(index);
+            const label timeIndex = IOdictionary(io).get<label>("index");
+            timeName = Foam::name(timeIndex);
         }
         else
         {
@@ -46,4 +31,3 @@
     }
 
     Info<< "\nTime [" << timeName << "] = " << runTime.timeName() << nl;
-