cosmoV_throw() now resets the vm stack as well

also a minor GC bug in cosmoO_newError was fixed.

i'm going to try to phase out cosmoM_freezeGC & friends
since that would cause hell with this new
error handling solution. the only thing still using it is the GC.

src/cbaselib.c

@@ -948,16 +948,9 @@ int cosmoB_vnewindexBProto(CState *state, int nargs, CValue *args)
 // vm.collect()
 int cosmoB_vcollect(CState *state, int nargs, CValue *args)
 {
-    // first, unfreeze the state (we start frozen on entry to any C Function)
-    cosmoM_unfreezeGC(state);
-
     // now force a garbage collection
     cosmoM_collectGarbage(state);
 
-    // and re-freeze the state
-    cosmoM_freezeGC(state);
-
-    // the end!
     return 0;
 }