Sega Sammy Holdings (6460.T-JP: Tokyo) has announced plans to acquire Finland-based Rovio Entertainment for 706 million euros (about $776 million).  The tender offer bid will be launched around May 8.  The offer represents a 19% premium over the current stock price. Analysis Rovio is noted for the Angry Birds franchise which in recent years has enjoyed most of its success on mobile platforms.  Angry Birds was released in 2009 and was an early mobile.....