Revise Linode API Docs url
added disk.createfromimage and disk.imagize
added account.estimateinvoice and account.list
added image.list and image.delete
added avail.nodebalancers
Merge branch 'master' into linode_support_update

Conflicts:
	spec/linode/avail_spec.rb
	spec/linode/linode/disk_spec.rb
whitespace :lipstick:
update to match newer mocha syntax
update docs paths to finally use https
use account.info instead of list

c.f.: https://www.linode.com/api/account/account.info
update README with credits
Merge pull request #25 from rick/land-displague/linode_support_update

Land pull request #23 ("Added support for additional API methods including disk imaging")