Takes a string as input, removes all non-letter characters, applies a caesar shift cipher of 3, and formats the output into blocks of 5 uppercase characters padded with Xs.
For example, given the input string:
Hello, this is a test!
the output will be:
KHOOR WKLVL VDWHV WXXXX
Type gradlew run to run the application.
Type gradlew test to run the unit tests.
To import into Eclipse, type gradlew eclipse, and then import as
an existing project.