ENH: simplify method names for reading argList options and arguments

- use succincter method names that more closely resemble dictionary
  and HashTable method names. This improves method name consistency
  between classes and also requires less typing effort:

    args.found(optName)        vs.  args.optionFound(optName)
    args.readIfPresent(..)     vs.  args.optionReadIfPresent(..)
    ...
    args.opt<scalar>(optName)  vs.  args.optionRead<scalar>(optName)
    args.read<scalar>(index)   vs.  args.argRead<scalar>(index)

- the older method names forms have been retained for code compatibility,
  but are now deprecated

applications/utilities/mesh/manipulation/rotateMesh/rotateMesh.C

@@ -83,10 +83,10 @@ int main(int argc, char *argv[])
     #include "setRootCase.H"
     #include "createTime.H"
 
-    vector n1(args.argRead<vector>(1));
+    vector n1(args.read<vector>(1));
     n1 /= mag(n1);
 
-    vector n2(args.argRead<vector>(2));
+    vector n2(args.read<vector>(2));
     n2 /= mag(n2);
 
     const tensor rotT(rotationTensor(n1, n2));