Set the indent as 4 spaces

[zhaiyusci]

According to style guide, set the indent for Julia as 4 spaces.

[carlobaldassi]

Thanks. This introduces a new option and thus it should be documented.
Also, the settings should be undone when the plugin is unloaded.

[carlobaldassi]

I'm not too sure about the name julia_recommended_style for the variable name. It seems very general, while this is only for indentation. Maybe julia_set_indentation?

[carlobaldassi]

Thanks!