Allow using the key 'Filename' when using FindProfileByProperty
Always return the error if any sync method failed

It seems we could rely on the structure being zeroed by coincidence, which fails sometimes.
Add cd_icc_save_data() so that we can set _ICC_PROFILE without re-reading the file
Fix GObject introspection when getting metadata

It's proper to return a container when returning a GHashTable array, although
nothing bad seems to happen if we return full.
Add a way to set the CdIcc filename manually

This may be required if the CdIcc object has been loaded from an on-disk cache.
Add CdIccStore to monitor directories of ICC profiles

This allows clients to watch special directories and be notified when profiles
are deleted or created.