Also support extended sd file list (including size in bytes) from printer

 See also #486 where support for SD_EXTENDED_DIR format was requested between the lines ;)
Merge branch 'devel' into commRefactoring
And even more work, trying to get the SD stuff and the offsets working again, also refactored some things here and there
Forgot to adapt verifyFileExists to new sd file list format
Merge branch 'devel' into commRefactoring