Use Array<Dynamic> for all object arrays, and cast output of the getting functions

git-svn-id: http://haxe.googlecode.com/svn/trunk@6519 f16182fa-f095-11de-8f43-4547254af6c6
clarified haxe.macro.Compiler.keep behavior

git-svn-id: http://haxe.googlecode.com/svn/trunk@6520 f16182fa-f095-11de-8f43-4547254af6c6
Merge branch 'haxe/master'