Update download urls to use the original bitbucket ones.

* Now downloads are done via https
* They generate a temporary url on s3.

Signed-off-by: François de Metz <francois@stormz.me>
Add -L option to curl to follow redirect.

Signed-off-by: François de Metz <francois@stormz.me>
Merge pull request #33 from francois2metz/update_urls

Update download urls