0025748: Parallel version of progress indicator

Progress indication mechanism is refactored to support incrementing progress within multithreaded algorithms.

The class Message_ProgressIndicator is only an interface to the user application.
It accumulates the progress provided by progress scopes.
The counter is protected by mutex for thread-safety.

The new class Message_ProgressScope replacing Message_ProgressSentry should be used to advance the progress.
The scopes are nested to each other to reflect the nested nature of operations.
The new class Message_ProgressRange should be used to pass the progress to sub-scopes.

All OCCT algorithms involving progress indication have been updated to new API.

Improvements in Draw_ProgressIndicator:
- Separate console mode has been added in order to make possible to put the progress into std::cout instead
  or in addition to the draw interpreter, instead of trigger option "-tclOutput".
- Treatment of Ctrl-Break signal has been added.
  Now any operation can be aborted by Ctrl-C or Ctrl-Break keystroke.

Added new test case 'perf fclasses progr_par' for testing of parallel work of the progress.

tests/perf/fclasses/progr_par

@@ -0,0 +1,13 @@
+puts "# ========"
+puts "# 0025748: Parallel version of progress indicator"
+puts "# ========"
+puts ""
+
+pload QAcommands
+
+XProgress +t
+
+set out [OCC25748 -niter 10000 -matsize 100 -parallel -progr]
+if {[llength [split $out \n]] != 103} {
+  puts "Error: unexpected number of lines in the output, must be 103"
+}