[woff2] Handle TTCs and start reconstructing font.

We `handle' TTCs by modifying the `indices' array to point to only
those tables that are part of the requested `face_index'.

Set and use `num_tables' in `WOFF2_TtcFont'.

* src/sfnt/sfwoff2.c (reconstruct_font): New function.
(woff2_open_font): Start reconstruction of font.
2 files changed