Short Description: Added support method for Method execution time display str.
Bug Number: n/a
Release notes (y/n): No
For Release Nums: 5.3

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Sim/Method.hpp
Sim/Method.cpp
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Added "Method" (Sim class) static method to provide a display string for 
each of the Method execution times:

RWCString Method::executionTimeDisplayStr (ExecTime et)
{
  // NOTE: These strings should NOT be used for model file serialization.
  // We may want to change these strings, and that shouldn't break the 
  // loading of previously saved model files.

  // NOTE: We may want to parameterize this method, either with a 'terse'
  // flag (for shorter versions), and/or if necessary, the "application"
  // as defined by the Category::Application, i.e. SIMULATION,
  // OBJECT_LEVEL_ACCOUNTING, or ACCOUNT_LEVEL_ACCOUNTING (if that
  // distinction is relevant).

  ...
}