Bug 753986 - manage layer resource block lnsr

Layer name source (id on 4 characters encoded in MacRoman).
psd from PS>5 have "luni" (Layer Unicode)

See https://bugzilla.gnome.org/show_bug.cgi?id=753986#c4 for more details

Janitorial on lyvr:
move IFDBG at the beginning of the function
+change the content of it