Support for Visual Studio 2015

[gkantsidis]

Can you add support for VS2015?
It seems that the only thing needed is to allow 14.0 in the sets of Set-VsVars and Get-VsVars (and adjust the comments).

(Vitallium also had problems with VS2015 in a previous post.)

[jcouv]

I'm getting the same problem.

The variable cannot be validated because the value 14.0 is not a valid value for the Version variable.
At C:\Users\Julien\Documents\WindowsPowerShell\Modules\Posh-VsVars\Posh-VsVars.psm1:116 char:32
+   if ($version -eq 'latest') { $version = Get-LatestVsVersion }
+                                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : MetadataError: (:) [], ValidationMetadataException