Move lines of code calculation to the server

Companion PR to to dashboard [PR](https://github.com/code-dot-org/dashboard/pull/90)
Remove blockly counting of lines of code (session based)
Report lines of code as part of the milestone call to the service (for all attempts - passing or failing)
Use server response to determine all-time total lines of code (could be session based or per-user in the db)
Changed report() to take an object - there were just too many parameters!