[woff2] Create stream for uncompressed buffer.

Uncompressed buffer is now an `FT_Stream'.

Perform basic checks and start iterating over tables.

* src/sfnt/sfwoff2.c (stream_close, find_table, read_num_hmetrics):
New functions.
(reconstruct_font): Modify parameters and iterate over tables.
(woff2_open_font): Updated.
2 files changed