allow to create a Crc instance to run progressively (used by hxformat)

git-svn-id: http://haxe.googlecode.com/svn/trunk@5859 f16182fa-f095-11de-8f43-4547254af6c6
changed fun.callback to fun.bind

git-svn-id: http://haxe.googlecode.com/svn/trunk@5860 f16182fa-f095-11de-8f43-4547254af6c6
resume from callback errors

git-svn-id: http://haxe.googlecode.com/svn/trunk@5861 f16182fa-f095-11de-8f43-4547254af6c6
Merge branch 'haxe/master'