Implement roleNames, remove call to setRoleNames
as setRoleNames is deprecated in Qt5.

This commit does not change functionality but helps to keep the same
codebase for Qt4 and Qt5
Fix harmattan roles
In Qt4 roleNames() is not virtual thus we need the explicit call to
setRoleNames().
Merge pull request #30 from lukedirtwalker/change_list_models

Change list models