License change : MIT License to Apache License, Version 2.0

[watermint]

There is no impact for most of existing users of watermint toolbox.
The change is intended to clarify the scope of protection by changing the licence to one with a stricter definition.
As the Apache License, Version 2.0 is a well-known and proven licence, I believe that there will be no disadvantages in its use.
This change was effective from Release 130.

• Issue - License change: MIT License -> Apache License Version 2.0 #811