Export interface to Vger

[ruza-net]

Often I find myself in a situation where I need to explicitly reference interface to Vger (usually while declaring a helper function to use in canvas). However, putting vger-rs into Cargo.toml and using that often results in type conflicts. The reason for that is a conflict of vger-rs versions used in rui and that included in the user project.

The best solution I found is in the commit; just pub use vger::{ .. }. One day, it might be better to make a submodule in rui, but for my current needs, this worked just fine.

[wtholliday]

Thanks!