Modified the display during the download: don't clutter several lines…

[gustavklopp]

… on the terminal, percentage of the current download display

[dessant]

Thanks a lot for this. It works with python 2, but it doesn't report the progress as it happens.
The file is dowloaded while Preparing to download http://github.com/kivy-garden/garden.cefpython/archive/master.zip ... is displayed, and after the download, the percentage counter just zips up to 100%.

On python 3, i get this:

Preparing to download http://github.com/kivy-garden/garden.cefpython/archive/master.zip ...
 Traceback (most recent call last):
   File "/home/vix/dev/venvs/py3/bin/garden", line 226, in <module>
     GardenTool().main(sys.argv[1:])
   File "/home/vix/dev/venvs/py3/bin/garden", line 84, in main
     options.func()
   File "/home/vix/dev/venvs/py3/bin/garden", line 140, in cmd_install
     fd = self.download(src_package)
   File "/home/vix/dev/venvs/py3/bin/garden", line 201, in download
     size = int(r.headers['Content-Length'].strip())
   File "/home/vix/dev/venvs/py3/lib/python3.4/site-packages/requests/structures.py", line 54, in __getitem__
     return self._store[key.lower()][1]
 KeyError: 'content-length'

[gustavklopp]

It zaps to 100% without installing anything? (if you've already downloaded it -or the file is small-, I can't see the progress neither. In fact, the longer is for python-requests to "prepare" the download apparently)

About the error with no Key 'content-length', I've got sometimes the same problem after trying it several times.... Strange. Maybe a connection problem to download this big file? I've put a "try...except"...