Deprecation of Browser[Browser.name] and documentation of Browser.parse

What I'd like to do instead of #2582.

Deprecate Browser[Browser.name], since their primary use is sniffing to activate/deactive functionality, but keep the useful features (for information and statistics) of userAgent strings.

It comes with a lot of Docs changes, probably easiest to look at it commit-by-commit, or to look at the "rendered" diff for the [docs file](#diff-0), or jump right to the [source file](#diff-1).