Do not create files for sections by default

[arai-a]

currently .grammar, .strings, and .tree files are created by binjs_encode, which are I think only for debug purpose. so it should be created only if some parameter is specified.

[arai-a]

this is troublesome for automation (batch encoding) with non-filter mode.

[Yoric]

That sounds like a bug.

[Yoric]

It shouldn't be too hard to fix. How quickly do you need it fixed?

[arai-a]

the issue happens only with non-filter mode, and the automation in m-c is using filter mode only. so not urgent for me.

[Yoric]

For what it's worth, I have fixed this in the entropy coder.

[arai-a]

do you mean they're not created if entropy encoding is used? or you've fixed this issue?

[Yoric]

The former. I should be able to backport some of the code to multipart if needed.