supporting gcutil 1.5.0

Hi Chirag,
I'm Riccardo and work on Google Compute Engine.
I was trying to use your gem (brilliant!) and I think I found a bug:

--project_id should be deprecated in favor of --project.

In machine creation it seems to work, but in retrieving list it breaks. Look:

$ knife google server list -VV --project google.com:discoproject
WARNING: No knife configuration file found
DEBUG: Using configuration from 
DEBUG: Linux Environment
DEBUG: Executing gcutil getproject --project_id=google.com:discoproject

DEBUG: Executing gcutil listinstances --print_json --project_id=google.com:discoproject
/var/lib/gems/1.8/gems/knife-google-0.0.1/lib/chef/knife/google_server_list.rb:83:in `run': private method `select' called for nil:NilClass (NoMethodError)
	from /var/lib/gems/1.8/gems/knife-google-0.0.1/lib/chef/knife/google_server_list.rb:81:in `each'
	from /var/lib/gems/1.8/gems/knife-google-0.0.1/lib/chef/knife/google_server_list.rb:81:in `run'
	from /var/lib/gems/1.8/gems/knife-google-0.0.1/lib/chef/knife/google_server_list.rb:76:in `each'
	from /var/lib/gems/1.8/gems/knife-google-0.0.1/lib/chef/knife/google_server_list.rb:76:in `run'
	from /var/lib/gems/1.8/gems/chef-10.18.2/lib/chef/knife.rb:408:in `run_with_pretty_exceptions'
	from /var/lib/gems/1.8/gems/chef-10.18.2/lib/chef/knife.rb:168:in `run'
	from /var/lib/gems/1.8/gems/chef-10.18.2/lib/chef/application/knife.rb:123:in `run'
	from /var/lib/gems/1.8/gems/chef-10.18.2/bin/knife:25
	from /usr/local/bin/knife:19:in `load'
	from /usr/local/bin/knife:19

I hope my small change helps.