Added the final keyword to all immutable variables.

I have discovered in horror that many variables are not modified during their lifetime, and yet lack the 'final' keyword. Is this really "enterprise-ready" software? 

According to industry best practices, all immutable variables (i.e. variables that do not change values during execution) should have the 'final' keyword. Otherwise, this supposedly robust package would collapse in a smouldering pile of ashes in a few months of heavy maintenanace. I can already detect some signs of decay in the smaller files, obviously due to lack of the 'final' keyword.