var-symbol provides the obvious complement operation to resolve. Where resolve maps from a symbol to a var by resolving it in the environment, var-symbol allows a user to recover the root binding symbol from a var if the var is named. If the var is not named, var-symbol returns nil.
This is related to CLJ-1488 in that it handles the common case of symbolically manipulating Vars in terms of the Symbols they bind without requiring that users manually reconstruct the bound symbol. Futhermore this patch nicely handles the non-obvious implementation consequent case of an unnamed var.
Depends on CLJ-1488
