Attempt to add a pack-info file
Attempt to use pack-info to count objects
Fix pack.info usage

- Finding commit parent tree only use pack info
- Finding objects to retrieve for pack creation
  only use pack info
Catch exception for a delete root fails
Dirty workaround for broken pipe
Fix indent
Pack .info improvements

* Activate even gevent is not activated
* Try to minimize the struct size
* Change from pickle to json serialization
* Add a small test pack_info_create
Add HTTP TIMEOUT delay for gevent connections

Value can be set in the configuration file.
Fix unused import of threading
Move TODO on top
Gevent is mandatory do the use of geventhttpclient

* Remove checking of gevent library as we
  now use geventhttpclient to perform requests