Provide Mechanism for Default Translation Text

[pfolta]

Issue

As of now, if one or more texts are missing in a language file, SortSimulation will crash and exit with a fatal error message ("Failed to parse resource files"), effectively preventing the use of partial language files.

Solution

Include default (English) text in source code. SortSimulation can then fall back to the default text if the key is missing in the active language file. This allows to use partial translations (i.e. using French localization with several, not yet translated, English texts).