Change the name of the default package to a list with one empty string
(instead of a void list of string). This is needed to be consistent with
the way the Java backend manages it. Consistency between front-end and
backend in this regard is necessary to solve
https://github.com/ceylon/ceylon-ide-eclipse/issues/761
Merge pull request #861 from davidfestal/master

Necessary change to solve https://github.com/ceylon/ceylon-ide-eclipse/issues/761