add EBDT and EBLC table support.

[mmulet]

This pull request adds basic parsing and validation for EBDT and EBLC tables in order to support bitmap fonts issue #200 .

It's been tested against the batang.ttc and guilm.ttc fonts supplied with the Korean Supplemental fonts in windows (after some small modifications to get the batang.ttc and guilm.ttc fonts to pass GSUB and CMAP sanitization). Those fonts
used Image formats 2 and 7 and EBLC index subtables 3 and 1. I'm still looking for other fonts that utilize the other index and image formats for testing.

Also, tested agains msmincho.ttc. which used subtable 2 and format 5.

Here is a list:

Tested fonts:

• msmincho.ttc
• batang.ttc
• gulim.ttc
• lucon.ttf
• msgothic.ttc
• simsun.ttc
• simsunb.ttf

Subtable Index format	Tested with production font
1.	YES
2.	YES
3.	YES
4.	YES
5	YES

Bitmap Image format	Tested with production font
1.	YES
2.	YES
3.	N/A
4.	N/A
5.	YES
6	NO
7	YES
8	YES
9	YES

Let me know what else has to be done to support bitmap fonts.

[dimdenGD]

Could someone review/merge this? It'd be great to add support for bitmap fonts.

[mmontag]

@khaledhosny friendly ping

[khaledhosny]

It is a quite some code and I don’t have much time to review it currently. But a first step would to provide a set of test fonts that we can add to the test suite, otherwise it is a big chunk of untested code.