static params: expr[T] is now static[T]

This introduces tyStatic and successfully bootstraps and handles
few simple test cases.  Static params within macros are no longer
treated as PNimrodNodes - they are now equivalent to constants
of the designated type.

compiler/jsgen.nim

@@ -130,7 +130,7 @@ proc mapType(typ: PType): TJSTypeKind =
     result = etyObject
   of tyNil: result = etyNull
   of tyGenericInst, tyGenericParam, tyGenericBody, tyGenericInvokation, tyNone, 
-     tyForward, tyEmpty, tyExpr, tyStmt, tyTypeDesc, tyTypeClasses: 
+     tyForward, tyEmpty, tyExpr, tyStmt, tyStatic, tyTypeDesc, tyTypeClasses: 
     result = etyNone
   of tyProc: result = etyProc
   of tyCString: result = etyString