Made sure files in core/ and tools/ have a proper Godot license header
when written by us. Also renamed aabb.{cpp,h} and object_type_db.{cpp,h}
to rect3.{cpp,h} and class_db.{cpp,h} respectively.
Also added a proper header to core/io/base64.{c,h} after clarifying
the licensing with the original author (public domain).
That year should bring the long-awaited OpenGL ES 3.0 compatible renderer
with state-of-the-art rendering techniques tuned to work as low as middle
end handheld devices - without compromising with the possibilities given
for higher end desktop games of course. Great times ahead for the Godot
community and the gamers that will play our games!
Done to ensure that no important identifiers are translatable,
to fix compound strings using the new vformat() function, and
some general English proofreading here and there.
