#203 rule: string case conversion without locale

[Hamlet D'Arcy]

Dm: Consider using Locale parameterized version of invoked method (DM_CONVERT_CASE)

A String is being converted to upper or lowercase, using the platform's default encoding. This may result in improper conversions when used with international characters. Use the

* String.toUpperCase( Locale l )
* String.toLowerCase( Locale l )

versions instead.