launcher.py: Avoid shell=True to consume half as many processes

No idea if "python2" will be converted to anything meaningful on Windows,
but then you're not really supposed to use the shell either in that dungeon.
https://docs.python.org/2.7/library/subprocess.html#subprocess.Popen

launcher.py

@@ -82,9 +82,9 @@ def main():
         # typically they don't provide any crawl-delay value in their robots.txt).
         if started and wikidir: #then resume
             print 'Resuming download, using directory', wikidir
-            subprocess.call('./dumpgenerator.py --api=%s --xml --images --resume --path=%s' % (wiki, wikidir), shell=True)
+            subprocess.call(['python2', 'dumpgenerator.py', '--api={}'.format(wiki), '--xml', '--images', '--resume', '--path={}'.format(wikidir)], shell=False)
         else: #download from scratch
-            subprocess.call('./dumpgenerator.py --api=%s --xml --images --delay=1' % wiki, shell=True)
+            subprocess.call(['python2', 'dumpgenerator.py', '--api={}'.format(wiki), '--xml', '--images'], shell=False)
             started = True
             #save wikidir now
             for f in os.listdir('.'):