Adding Arduino Mega 2560 board entry.
Adding Arduino Mega 2560 board entry.


Former-commit-id: 4ab27234d3993af28a250a5ccd4d3d8d32241a91
tintin304/chipKIT32-MAX,ricklon/chipKIT32-MAX,tintin304/chipKIT32-MAX,chipKIT32/chipKIT32-MAX,adamwolf/chipKIT32-MAX,adamwolf/chipKIT32-MAX,EmbeddedMan/chipKIT32-MAX,ricklon/chipKIT32-MAX,chipKIT32/chipKIT32-MAX,adamwolf/chipKIT32-MAX,tintin304/chipKIT32-MAX,majenkotech/chipKIT32-MAX,chipKIT32/chipKIT32-MAX,EmbeddedMan/chipKIT32-MAX,ricklon/chipKIT32-MAX,chipKIT32/chipKIT32-MAX,chipKIT32/chipKIT32-MAX,tintin304/chipKIT32-MAX,adamwolf/chipKIT32-MAX,EmbeddedMan/chipKIT32-MAX,tintin304/chipKIT32-MAX,majenkotech/chipKIT32-MAX,adamwolf/chipKIT32-MAX,EmbeddedMan/chipKIT32-MAX,ricklon/chipKIT32-MAX,ricklon/chipKIT32-MAX,adamwolf/chipKIT32-MAX,chipKIT32/chipKIT32-MAX,majenkotech/chipKIT32-MAX,adamwolf/chipKIT32-MAX,chipKIT32/chipKIT32-MAX,EmbeddedMan/chipKIT32-MAX,majenkotech/chipKIT32-MAX,majenkotech/chipKIT32-MAX,ricklon/chipKIT32-MAX,ricklon/chipKIT32-MAX,EmbeddedMan/chipKIT32-MAX,EmbeddedMan/chipKIT32-MAX,majenkotech/chipKIT32-MAX,majenkotech/chipKIT32-MAX,tintin304/chipKIT32-MAX,tintin304/chipKIT32-MAX