Add String::{ubegin,uend}.
Cmap fix: check_table was returning the wrong value.

check_table(t) is expected to return the correct table index for
table t. Formerly, it returned 0 after the first call.
Cmap helper.
otfinfo: Make -g work with TTFs, add -u/--unicode.
Avoid crappy post tables that define the same glyph name multiple times.
Prepare release.