(read_name): Argument changed. Set

(read_name): Argument changed.  Set
OTF_NameRecord->ascii.  If possible, convert Unicode sequence to
ASCII.
(read_name_table): Adjusted for the change of read_name.
(read_cmap_table): Signal an error (not-yet-supported) if format
is 2.  Support for formats, 8, 10, 12.
(read_value_record): Clear value_record at first.
(read_lookup_subtable_gpos): Fix for the case subFormat is 1 and
2.
(OTF_open): Check file name extension.