Readme - License & Author

[javier-godoy]

The License & Author paragraph starts with the sentence:

-Add-on is distributed under Apache License 2.0. For license terms, see LICENSE.txt.

while in other add-ons we agreed on

+This add-on is distributed under Apache License 2.0. For license terms, see LICENSE.txt.

Moreover, this add-on lists the initial commiters to the repository,

-TwinColGrid Add-on was written by
-
- Felipe Lang
- Martin Lopez

while in other add-ons just mention

+<Name of the add-on> is written by Flowing Code S.A.