get rid of syncqt wrapper scripts

instead, rename it to syncqt.pl and rely on qtPrepareTool()'s new
ability to correctly invoke it as a perl script even under windows.
the wrappers themselves have been trivial at this point, so there is no
added value in keeping them, either.

Change-Id: I77cf65edbcfaa48ed1900defe940d4eb4b82d5b9
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>