Added rax_extensions() method to load all rax extensions
Seams to work on volumes controller, but not on limits
Added rax-admin resource extension
Changed name to quota-usage and added top-usage
updated README.md
Fixed comment and added authorize methods for top-usage and quota-usage
No longer throwing exceptions if top-usage or limit is null, added SafeDict() so this solution is reusable for future rax-admin methods
Merge pull request #6 from thrawn01/quota-list

Add rax-admin extension to the project