Bug 1341215 - Vendor dlmanager. r=chmanchester

from https://github.com/parkouss/dlmanager

Note this technically should come before the first patch, but mozreview
won't show useful interdiffs if I do that, so I'll reorder the patches
before landing.

python/dlmanager/examples/dl_progressbar.py

@@ -0,0 +1,41 @@
+import argparse
+
+# for python 3, use https://github.com/coagulant/progressbar-python3
+from progressbar import ProgressBar, Percentage, RotatingMarker, ETA, \
+    FileTransferSpeed, Bar
+
+from six.moves.urllib.parse import urlparse
+
+from dlmanager import Download
+
+
+def parse_args(argv=None):
+    parser = argparse.ArgumentParser()
+    parser.add_argument("url", help="url to download")
+    return parser.parse_args(argv)
+
+
+def download_file(url, dest=None):
+    if dest is None:
+        dest = urlparse(url).path.split('/')[-1]
+
+    widgets = ['Download: ', Percentage(), ' ', Bar(marker=RotatingMarker()),
+               ' ', ETA(), ' ', FileTransferSpeed()]
+    bar = ProgressBar(widgets=widgets).start()
+
+    def download_progress(_, current, total):
+        bar.maxval = total
+        bar.update(current)
+
+    dl = Download(url, dest, progress=download_progress)
+    dl.start()
+    dl.wait()
+    bar.finish()
+
+
+if __name__ == '__main__':
+    options = parse_args()
+    try:
+        download_file(options.url)
+    except KeyboardInterrupt:
+        print("\nInterrupted.")