ENH: add some system information when outputting profiling

- basic cpuInfo (model identification, MHz, etc)
- process memInfo

- profiling is activated via the case system/controlDict by
  adding a "profiling" sub-dictionary.

  Simply add the following (everything enabled):

      profiling
      {}

  Which corresponds to the longer form:

      profiling
      {
          active      true;  // default: true
          cpuInfo     true;  // default: true
          memInfo     true;  // default: true
          sysInfo     true;  // default: true
      }

  This can be used to selectively disable any extra information
  (eg, you don't want anyone else to know what hardware was used).