added system.compiles

todo.txt

@@ -18,6 +18,8 @@ New pragmas:
   - fix evals.nim with closures
   - implement "closure tuple consists of a single 'ref'" optimization
   - make closure default calling convention for proc types
+  - make 'raiseHook' take a closure and provide push and pop for this
+    --> Lisp-style exception system
 
 - document 'do' notation
 - rethink the syntax: distinction between expr and stmt is unfortunate;