Beginnings of graph support with Flot (only directly dependent free numbers graph correctly right now). Refactor solver into the parser. Have the expression remember the op tree so we can do substitution. Make free number marks preserve over time. Rewrite some connect logic. A lot of other small fixes.
Change scale of graphs. Quick fix to avoid indep. graph being drawn many times due to weird mousedown event repetition.
Graph axes move and stay at constant scale while scrubbing.
Make free markers uninclusive when not replacing their values.
More intuitive = key behavior (deletes right side of equation if there's already one).
Switch to Newton's method and delete Numeric.js. Ridiculous speed increase. Also small cleanups.
Line state is handle-based now. Equals signs get replaced so the truth of what's onscreen is always preserved. Add a bound on solver iterations.
Change scrubbing behavior. Fix small bug with number widget placement while equals sign is > or <.