If you have not noticed there is an incredible Microsoft Dynamics CRM Software Developers Kit (SDK), but in previous versions of the SDK there were also a set of visual studio tools.
Working in Technology? As We Know Change is A Constant
So lets look at some changes
Visual Studio Tools for Microsoft Dynamics CRM are now available as part of Visual Studio. Check out these to get started
and there are a ton more available and always more coming -> use SEARCH
You can also use the Microsoft Dynamics CRM 2013 SDK Visual Studio Tools with Microsoft Dynamics CRM 2015. You update your references to point to the new SDKdlls and update the framework version to 4.5.2.
There are a number of different blog posts buzzing on this, Such as these:
You also need to consider CRM Online and the reality that the current version of CRM Online is v7.1.x and the version of CRM On-Premise is v7.0.1 (although only a few months behind). One of the huge benefits of working with a CRM Online model is the drip feed to stay current. Huge Upgrades are a thing of the past when it comes to Software as a Service (SaaS). This also changes the development and extension model.