fix for template redefinition. test cases added.

tests/compile/tredef.nim

@@ -0,0 +1,29 @@
+template foo(a: int, b: string) = nil
+foo(1, "test")
+
+proc bar(a: int, b: string) = nil
+bar(1, "test")
+
+template foo(a: int, b: string) = bar(a, b)
+foo(1, "test")
+
+block:
+  proc bar(a: int, b: string) = nil
+  template foo(a: int, b: string) = nil
+  foo(1, "test")
+  bar(1, "test")
+  
+proc baz =
+  proc foo(a: int, b: string) = nil
+  proc foo(b: string) =
+    template bar(a: int, b: string) = nil
+    bar(1, "test")
+    
+  foo("test")
+
+  block:
+    proc foo(b: string) = nil
+    foo("test")
+    foo(1, "test")
+
+baz()