remove unnecessary weak pointer locking and function calls from arc less than operator.  Speeds up large sims by ~1.7X
add missing virtual keyword for sqliteback::Notify func
Merge pull request #979 from rwcarlsen/fast-arc

remove weak pointer locking and extra function calls from Arc::operator<
Merge branch 'cyclopts' of github.com:gidden/cyclus into gidden-cyclopts
Merge branch 'cyclopts' of github.com:gidden/cyclus into gidden-cyclopts
Merge branch 'gidden-cyclopts' into develop