Browser ie11

Updates for specs and docs, and an optional last commit which is explained below:

Apparently after we decided on just doing the `Browser.modernie` thing in all versions, some people suddenly started having issues with it anyway. I don't feel like going through all of this again, so the last commit in my branch supports the second of two options we have. Just pull including the last commit if that is the way we go, ignore the last commit if we don't.

Both options being:

1. `Browser.ie` for IE<=10, `Browser.modernie` for IE>=11, in all versions.
2. `Browser.ie` for IE<=10, `Browser.modernie` for IE>=11, in compat build only, `Browser.ie` for all IE in "normal" build.

Note: I am not opposed to either option, it's just a different approach, and both have their benefits.