add pool for SystemProcess/Views

[fponticelli]

No description provided.

[dwzzz]

Not only need pool.
Each time SystemProcess call Views.iterator() will alloc extra a lot memory for for map.keys() and a little memory for anonymous function( hasnext(), next(), holder ) in every loop.

And another issue:
the Views T is anonymous type ,so in some special platform( e.g. C# ), the generated source codes will slower http://haxe.org/manual/types-structure-performance.html .
Can macro detect these anonymous structs and create new type class and replace them?

[fponticelli]

I believe the allocation problem is still there but I made a few tests of classes vs anonymous and I cannot find any real difference in terms of performances.