Open in PowerShell and conda environments

[huguesv]

There have been some changes to conda and now conda environments no longer have a conda.bat in their scripts folder.

Since we're not building UI to support every possible conda command, we need to ensure that when they click Open in Powershell, that conda.exe can be used.

[huguesv]

We need to include the root's scripts folder in PATH, because our VS-bundled Anaconda installation doesn't modify PATH. It should be included AFTER the conda env's scripts folder (which we already add to PATH).

In addition, we need to activate the conda env, so that when you run conda.exe operations, it actually applies to that environment.

For command line, we can run something like this:

cmd.exe /k "<path_to_root>\scripts\activate.bat" <env_name>

For powershell, there's no activate.ps1 at this time. There's an issue for that at conda/conda#626.

[kalefranz]

A contributed powershell wrapper to conda would be hugely appreciated. With conda 4.4+, there are five other shell wrappers for conda. We're still obviously missing powershell.

I started the conda/conda#6471 PR as a sketch of what the powershell wrapper might look like, and Steve Dower added some additional comments in conda/conda#6471 (comment).

Eager to work with anyone wanting to push this through and get it in.