Tools for plugin dev for CRM 2015?

We are on CRM 2015 Update 1 Online. I want to know the "official" plugin development tools that I should be using to write plugins for this environment.

I am new to writing plugins and started working on CRM 2013 (SDK 2013, Developer Toolkit, VS2012) but we got upgraded to 2015 and nothing works the same anymore! Here's my current status:

- I installed .NET Framework 4.5.2 as told by MS. It now shows in VS when creating a new project.

- I have VS2012 and it has CRM code templates. Is it supported for CRM 2015 dev?

- I have VS2013 which is OK for CRM 2015 dev but it does not have CRM templates. What is the best way to get a CRM 2015 project started in VS2013? Is it OK to open a VS2012 project in VS2013 and start from there?

- SDK 2015 no longer has a Developer Toolkit. All the more reason to need a CRM template!

Thank you in advance for helping and pointing me in the right direction. I am looking for the official/supported way of doing things so that when MS change their mind again, I have to do the least amount of rework. Unlike what happened to me right now!!