added couple more FileUtils methods
cosmetic changes
when doing 'refresh' wipe all data about remote files which no longer exist on Remote
bundle name mud be unique

previous version returned as many bundle names as many file names found in bundle
final (hopefully) version of handling a situation when user is trying to save local aura file with Id which no longer exists on Remote

this happens when remote aura file is deleted
Have to be extra careful because someone else might have created aura file with same name and new Id