Created MP4 box parsers to parse data for common box types (shaka-pro…

…ject#2648)

added tkhd box parsing

unit testing for mp4 box parsers

moved mp4 box structs to lib/util

inlined returns for mp4 boxes

created mp4 parser to parse cea708 packets from mp4 streams (shaka-project#2648)

tightened array out of bound checks

added error code for invalid mp4 for cea packets

refactored name of mp4 cea parser interface

fixed a bug with increment ordering that affected time

linting

addressed mp4 cea parsing comments

stylistic changes to mp4 cea parser

improved mp4 parser comments and addressed pr review

return caption packets as array instead of in a callback

removed caption packets from class state to avoid clearing it in the middle of a parse

Implemented CEA-608 decoder

fix the diff

fix build and style fixing

removed new parser

bug fix for fields

build/types/cea

@@ -1,5 +1,7 @@
 # Inband closed caption support.
 
-+../../lib/cea/mp4_cea_parser.js
++../../lib/cea/atsc_decoder.js
++../../lib/cea/i_caption_decoder.js
 +../../lib/cea/i_cea_parser.js
++../../lib/cea/mp4_cea_parser.js
 +../../lib/cea/sei_processor.js