remove purge functionality

This is no longer needed since all tests use a live server.
remove unreachable code
remove unused get_{in,out}put{,s} methods
remove unused get_input{,s} from input holder
Merge pull request #11 from genome/remove-unused-code

Remove unused code
Update README.md
Merge pull request #12 from genome/rename

Rename
More descriptive error
Make quotes consistent in test data structures
Fix nested inputs in api tests
Remove 'type' from api tests
Rename link to edge
Use camelCase for Edge properties
Just a little change from operation to node