Here is SOLUTION to your problem that I fixed in 2 minutes.
This extension can be installed on every version of VS 2015.
Here is how:
1. Download the file.
2. Rename the Entity Framework Power Tools Beta 4.vsix ( to .zip, .7zip or .rar file. You will be prompted and say YES, do that ).
3. Open the file using 7zip and look for the file: "extension.vsixmanifest" open that by clicking "EDIT" in 7zip.
4. In the file which is an XML file behind:
Pro
// This is a comment dint include this! Add these three lines to it install and enjoy! //
Add this section
Pro
Enterprise
Comunity
5. Save the file by clicking exit and saying YES!
6. Rename file again to .vsix file extension and you all done install your extension and enjoy!
Add this section
