set correct max size for mega2560 (to address issue #2277)

Signed-off-by: Arnav Gupta <championswimmer@gmail.com>
Merge pull request #2316 from championswimmer/1.0.x-fixMaxMega

set correct max size for mega2560 (to address issue #2277)
Fix typo in KeyboardLogout.ino

Comment says ALT+s, code says ALT+l. This remedies that difference.
Add #include "Print.h" in Server.h
Add #include "Print.h" in Server.h
[sam] Fixed compile error when using math functions

Fixes #2338
Merge pull request #2329 from Unh0lyTigg/patch-1

Fix typo in KeyboardLogout.ino
Merge pull request #2330 from spiritinlife/ide-1.5.x

Add #include "Print.h" in Server.h    Ide 1.5.x
Merge branch 'master' into ide-1.5.x. Updated revision log.

Conflicts:
	build/shared/examples/09.USB/Keyboard/KeyboardLogout/KeyboardLogout.ino
	hardware/arduino/boards.txt
Fixed typos in MailboxReadMessage example