Add initial OpenStack support
Don't use LWP::UserAgent shortcuts

Try as much as possible to don't rely on LWP::UserAgent shortcuts for
HTTP requests in order to minimize version dependency issues.
Refactor request handling into a _request method
Add list_instances method
Add list_running_instances method
Add stop_instance method
Add start_instance method
Add vim modelines
Reindent
Add proxy support via *_proxy environment variables
Use hash for _request parameters instead of array
Add missing strict and warnings pragmas
Add a pinch of logging
Add list_flavors method
Add list_images method
Add get_cinder_url method
Add create_volume method
Add delete_volume method
Add list_volumes method
Add attach_volume method