setFields: Added time options -constant, -latestTime, -noZero, -time

in particular to support setting constant property fields in the constant
directory.

Usage: setFields [OPTIONS]
options:
  -case <dir>       specify alternate case directory, default is the cwd
  -constant         include the 'constant/' dir in the times list
  -dict <file>      read control dictionary from specified location
  -fileHandler <handler>
                    override the fileHandler
  -hostRoots <((host1 dir1) .. (hostN dirN))>
                    slave root directories (per host) for distributed running
  -latestTime       select the latest time
  -libs '("lib1.so" ... "libN.so")'
                    pre-load libraries
  -noFunctionObjects
                    do not execute functionObjects
  -noZero           exclude the '0/' dir from the times list
  -parallel         run in parallel
  -region <name>    specify alternative mesh region
  -roots <(dir1 .. dirN)>
                    slave root directories for distributed running
  -time <time>      specify a single time value to select
  -srcDoc           display source code in browser
  -doc              display application documentation in browser
  -help             print the usage

applications/utilities/preProcessing/setFields/setFields.C

@@ -408,8 +408,18 @@ int main(int argc, char *argv[])
 {
     #include "addDictOption.H"
     #include "addRegionOption.H"
+    #include "addTimeOptions.H"
     #include "setRootCase.H"
     #include "createTime.H"
+
+    // Get times list
+    instantList Times = runTime.times();
+
+    // Set startTime and endTime depending on -time and -latestTime options
+    #include "checkTimeOptions.H"
+
+    runTime.setTime(Times[startTime], startTime);
+
     #include "createNamedMesh.H"
 
     const dictionary setFieldsDict(systemDict("setFieldsDict", args, mesh));