Add Vm::frames(&self) function

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

src/vm/mod.rs

@@ -48,6 +48,11 @@ impl<'c> Vm<'c> {
         self.frames.last_mut()
     }
 
+    /// Gets the list of stack frames.
+    pub fn frames(&self) -> &Vec<Frame> {
+        &self.frames
+    }
+
     /// Gets the stack.
     pub fn stack(&self) -> &Vec<ObjRef> {
         &self.stack