Linesofcode

Track lines of code - as part of Activity (note that Activity will include lines of code even for failed attempts)
Track lines of code (all time) - as part of User (note that this total count only includes successful attempts)
Track lines of code - stored in session[:lines] for anonymous users (total - only successful)
Track level progress (best results) - stored in session[:progress] for anonymous users
Modify UX header to leverage anonymous level progress

Note: this requires a blockly change to submit lines of code in the milestone report