Avoid passing null as the appName to ConsoleKeys.

The code above default this.appName to "JLine", but then appName is
passed directly to ConsoleKeys.  Instead, pass this.appName so that
ConsoleKeys can make use of the default "JLine" application name when
processing a user's ~/.inputrc file.
Merge pull request #119 from jszakmeister/pass-correct-appname

Avoid passing null as the appName to ConsoleKeys.