With the impending Salesforce spring release here are the main developer based changes:
Apex Flex Queue
Get more flexibility in managing your batch jobs. Submit up to 100 batch jobs simultaneously and actively manage the order of the queued jobs to control which batch jobs are processed first.
Lightning Process Builder Now GA
Visually Automate Your Business Processes with Lightning Process Builder, a workflow tool that helps you easily automate everything from daily tasks, like follow-up emails, to more complex processes, like order renewals and new-hire onboarding. In just a few clicks you can automate business processes and help your organization operate more efficiently.
New Lightning Components
The Lightning Component framework is a UI framework for developing dynamic web apps for mobile and desktop devices. It’s a modern framework for building single-page applications engineered for growth. The Lightning Component framework powers Salesforce1. Now, you can use the framework to create your own Lightning components and make them available to Salesforce1 users
Setup test data for an entire test class
Use test setup methods (methods that are annotated with @testSetup) to create test records once and then access them in any test method in the test class. Test setup methods are useful and can be time-saving when you need to create a common set of records that all test methods operate on or prerequisite data.
Enhanced Visualforce mapping components
REST API Enhancements
REST API includes new features, new resources, and changed resources in version 33.0. Highlights include the ability to insert and update Blob data, use of CORS to Access REST API and a new Limits resource.