Support for Sublime3

[cater]

Sublime3.0中通过view.is_read_only接口无法获得文件是否是只读，我修改了判断文件是否只读的接口，以支持Sublime3.0

[AxxL]

Google Translate: Sublime3.0 interfaces can not be obtained through view.is_read_only whether the file is read-only, I modified the judgment whether the file read-only interface to support Sublime3.0

Funny, that I can't reproduce that with build 3047.

[AxxL]

Does your pull reqest include code for changing the os-attributes of that file? My code never intended that. I only want to to change the view (buffer, file reperesentation of the view) to prevent an unintended editing. Like viewing a log-file which updates itself but must not edited by me. I don't want to change the attributes of the file in the operating system itself.

[cater]

Yes, in sublime2.0 calls the view.set_read_only changes the os-attributes ot that file.But not in sublime3.0.
I need to use this feature, so I made some changes to the code

[FranklinYu]

I think this pull request can be closed? Current version works in Sublime Text 3 without issue, and we do have the "Readonly" in status bar.