[BUG] Possible missing copy in `default_inserter`

[emstoudenmire]

In src/solvers/insert/insert.jl, should the variable state be copied at the beginning of the default_inserter function? Later in that function, there are lines modifying state such as state[v] = phi.

[mtfishman]

Good catch, agreed it looks like state should be copied at the beginning of default_inserter.