'lambda' is no keyword anymore

compiler/lexer.nim

@@ -40,7 +40,7 @@ type
     tkFinally, tkFor, tkFrom,
     tkGeneric, tkIf, tkImport, tkIn, tkInclude, tkInterface, 
     tkIs, tkIsnot, tkIterator,
-    tkLambda, tkLet,
+    tkLet,
     tkMacro, tkMethod, tkMixin, tkMod, tkNil, tkNot, tkNotin, 
     tkObject, tkOf, tkOr, tkOut, 
     tkProc, tkPtr, tkRaise, tkRef, tkReturn, tkShl, tkShr, tkStatic,
@@ -75,7 +75,7 @@ const
     "elif", "else", "end", "enum", "except", "export",
     "finally", "for", "from", "generic", "if", 
     "import", "in", "include", "interface", "is", "isnot", "iterator",
-    "lambda", "let", 
+    "let", 
     "macro", "method", "mixin", "mod", 
     "nil", "not", "notin", "object", "of", "or", 
     "out", "proc", "ptr", "raise", "ref", "return",