'nimfix' improvements; FdSet is TFdSet again

todo.txt

@@ -41,9 +41,8 @@ Misc
 
 - fix the bug that keeps 'defer' template from working
 - make '--implicitStatic:on' the default
-- fix the tuple unpacking in lambda bug
 - make tuple unpacking work in a non-var/let context
-- special rule for ``[]=``
+- special rule for ``[]=``, items, pairs
 - built-in 'getImpl'
 - type API for macros; make 'spawn' a macro
 - markAndSweepGC should expose an API for fibers
@@ -172,8 +171,6 @@ Not essential for 1.0.0
 - implement "closure tuple consists of a single 'ref'" optimization
 - new feature: ``distinct T with operations``
 - arglist as a type (iterator chaining); variable length type lists for generics
-- implement marker procs for message passing
-- implement closures that support nesting of *procs* > 1
 - object constructors: static check for fields if discriminator is known at 
   compile time
 - prove array accesses