0031763: Foundation Classes - reporting of progress within parallel algorithms

Classes Message_ProgressRange and Message_ProgressScope are improved to store start point of the range.
Method Message_ProgressScope::Value() is improved to compute the value in the current scope from the actual current value of the global progress.
Description of Message_ProgressScope class is improved.

Off-topic:
- method Message_ProgressScope::Relieve() is renamed to Close() for semantic consistency
- article in Upgrade Guide is revised and corrected

src/Draw/Draw_ProgressIndicator.cxx

@@ -202,7 +202,7 @@ Standard_Boolean Draw_ProgressIndicator::UserBreak()
     {
       OSD::ControlBreak();
     }
-    catch (OSD_Exception_CTRL_BREAK)
+    catch (const OSD_Exception_CTRL_BREAK&)
     {
       myBreak = Standard_True;
     }