add: Strategy
Add structure for checking ninja strategies.
Edit ninja approvals:

- moved error checking into the strategy
- fixed broken tests in services/approval and approval/default
- remove validate service
Add webhook strategy

- added entire vote object on vote
- added hook.js api for testing strategies webhook strategies
- added github login to vote
Fix test server/approval/default.js
Modify tool votes

- added valid-url and request to package.json (missing in previous commit)
- tools now vote with user='tool' and name=toolname
- some additional error checking
Add tests for webhook approval
Add commit sha to approval protocol
Merge pull request #118 from reviewninja/feature/ninja

Feature/ninja