* #21 made the standing controller a little bit slower. Could special-case `QuaternionFloating` (skip premultiplying the constraint by the full-rank matrix S^T). * improve handling of sum of many terms in SimpleQP for wrench balance constraint * don't call `modifyconstraint!` for `Constraint`s that have a fixed `LazyExpression` in SimpleQP.
QuaternionFloating(skip premultiplying the constraint by the full-rank matrix S^T).modifyconstraint!forConstraints that have a fixedLazyExpressionin SimpleQP.