Add browserName and tree-shaking

[IgorBabkin]

• add separate function to detect browser name
• add tree-shaking

[DamonOehlman]

@IgorBabkin looks good - thanks for this. Merging it in.

[DamonOehlman]

@IgorBabkin I'm about to publish the 5.0.0 version, which has been on the back-burner for a while now. No real breaking changes, so potentially qualifies for a minor release, but I'm pushing major anyway.

I'm pretty confident that all is well, but if you could take it for a spin and make sure everything works for your use case that would be appreciated.

[IgorBabkin]

@DamonOehlman I've checked browserName and detect. Everything is okay for me. Just only one question: it's needed to pass navigator.userAgent to browserName. Is it okay for you? And maybe we need to describe this function in Readme?