Makefile: Improve handling of WMake verbose output and errors

* The '-e' option has nothing to do with verbose output.
  It is now properly handled by .ERASE directive in make file

* The '-s' option sets silent output globally, it cannot be switched off.
  It is now handled only by .SILENT directive in make file directive
  is simply controlled by a conditonal block.

Remove SilentNoColon member variable as it is no longer needed.
Merge topic 'watcom-VERBOSE-and-ERROR' into next

f1b689b6 Makefile: Improve handling of WMake verbose output and errors