No translation for the two included key strings

There two text strings displayed in this plugin that are not translated. There is no pot file coming with this plugin, so I thought that it gets the translations by the main language file of WordPress which in my greek case is el.po. Although, these strings are translated in el.po, they are not shown on site!

Please fix.

These are the text string:

1. Site Tagline:

2. In a few words, explain what this site is about. Default will be used if left blank.