Store stemcell name & version at image properties
Fix 'wait_resource'

Fixed 'wait_resource' method to be more robust:
- Break the loop on :error and :failed states (instead of waiting
fot the full timeout)
- Default timeout is now 600 seconds
- nils on resources reload are only allowed if option is set
- Fixed also unit tests
- Improved method's documentation
Fix network configuration

- Check for security groups changes
- Extract security groups for dynamic and vip networks
- Improve floating IP allocation/deallocation routine
- Fixed unit tests (according to changes)
- Improve method's documentation
Upgrade bosh_cpi to v0.5.1
Allow CPI tasks to be cancelled
Upgrade rspec & guard gems
Updated CPI documentation
Fix availability zones in create vm and create disk
Added info messages when uploading kernel and ramdisk images
Added support for OpenStack regions
Use separate glance parms
Add logger accessor
Fix 'wait_resource' not returning symbols
Fix 'wait_resource' when resource is not found
Fix delete settings from registry
Handle resources not found
Handle server not found when rebooting
Added basic integration tests for VM lifecycle

To run integration test:
1. Prepare OpenStack CPI configuration file (a sample can be found at
   spec/assets/sample_config.yml);
2. Set CPI_CONFIG_FILE env variable to point to OpenStack config file;
3. Download a public OpenStack stemcell: 'bosh download public stemcell ...';
4. Untar the OpenStack stemcell, you'll find and image file;
5. Set STEMCELL_FILE env variable to point to OpenStack image file;
6. Start OpenStack Registry manually (see bosh/openstack_registry);
7. Run 'bundle exec rspec --color spec/integration/cpi_test.rb'.
Added single quotes to resource names
Log stemcell_id and instance_type when creating a new vm