rewrote lambdalifting; fixes deeply nested closures

tests/closure/tnestedclosure.nim

@@ -0,0 +1,36 @@
+discard """
+  output: '''foo88
+23 24foo 88
+foo88
+23 24foo 88'''
+"""
+
+# test nested closure
+proc main(param: int) =
+  var foo = 23
+  proc outer(outerParam: string) =
+    var outerVar = 88
+    echo outerParam, outerVar
+    proc inner() =
+      block Test:
+        echo foo, " ", param, outerParam, " ", outerVar
+    inner()
+  outer("foo")
+
+# test simple closure within dummy 'main':
+proc dummy =
+  proc main2(param: int) =
+    var foo = 23
+    proc outer(outerParam: string) =
+      var outerVar = 88
+      echo outerParam, outerVar
+      proc inner() =
+        block Test:
+          echo foo, " ", param, outerParam, " ", outerVar
+      inner()
+    outer("foo")
+  main2(24)
+
+dummy()
+
+main(24)