Add support for two IPA superscripts

[AshtarBalynestjar]

U+02B1 ʱ and U+02C0 ˀ represent breathy voice and glottalization, respectively. Note that although they don’t appear on the one-page IPA chart, they aren’t unofficial symbols; they have been used in official publications such as the Illustrations of Bengali (here) and Danish (not accessible for free) by the International Phonetic Association. I’d say that I’ve seen them used more often than some superscripts actually on the one-page chart, such as the ones for lateral and nasal release.

[pauldhunt]

Will add in next release.

[erniemarch]

confirm present in both roman and italic of 3.006 build