added commons-io dependency

HG-23
added RandomGreetingService and associated unit test

HG-23
added client-provided greetings resource

HG-23
added tests to demonstrate bug when name is empty or blank

By blank, I mean consisting of whitespace only.
added commons-lang as a dependency
modified generateGreeting to check name using StringUtils.isBlank

As suggested by hedgeninja, now we correctly handle all cases when the
name isn't specified
Merge pull request #4 from ceharris/randomGreetings

HG-23: RandomGreetingService