New onix values for crosswalk

[mattgarrish]

The following values appear to be new since the crosswalk was last updated:

Value	Label	Notes	Iss	Rev
25	Use of color	For readers with color vision deficiency, use of color (eg in diagrams) is not the sole means of graphical distinction	48
26	Use of contrast	Body text is presented with a contrast ratio of at least 4.5:1 (or 3:1 for large/heading text)	48
27	Use of audio	Audio content is presented with no or low background noise (eg ambient sounds), at least 20dB below the level of foreground speech	51
28	Full alternative audio descriptions	All or substantially all non-text content has full alternative descriptions as pre-recorded audio. Note this applies to normal images (eg photographs, charts and diagrams) and also to any embedded video etc. Video content should include full alternative descriptions (eg audio-described video) and transcript, subtitles or captions (whether closed or open) suitable for hearing-impaired as well as for visually-impaired readers. (Purely decorative non-text content can be ignored, but the accessibility of resources delivered via a network connection rather than as part of the e-publication package must be included)	51
29	Next / Previous navigation	All levels of heading and other structural elements of the content are correctly marked up and (if applicable) numbered, to enable fast next heading / previous heading, next chapter / previous chapter navigation without returning to the table of contents
93	Compliance certification by	carries the URL of a web page belonging to the organisation responsible for compliance testing and certification of the product – typically a ‘home page’ or a page describing the certification scheme itself. For use in ONIX 3.0 only	51	55

[LaZay]

Here other missing schema to ONIX translations.

• braille -> List 21 code BRL Braille edition, and also List 175 codes B701 UK Uncontracted Braille, B702 UK Contracted Braille, B703 US Braille, B704 US Uncontracted Braille, B705 US Contracted Braille, B706 Unified English Braille
• unlocked -> List 44 code 00 None + 02 Digital watermarking
• largePrint -> List 21 code LTE Large type / large - print edition
• transcript -> List 196 codes 15 Full alternative descriptions + 28 Full alternative audio descriptions ( a little more questionable though)