_load_textdomain_just_in_time error from Main::get_plugin_verison()

[afragen]

There seems to be to be a _load_textdomain_just_in_time error emanating from the get_plugin_data() call in Main::get_plugin_version(). By using get_file_data() instead this will mitigate the error. It seems that get_plugin_data() wants to try translating the headers, since we're only getting the version it shouldn't matter.