[bwyamshn] Base 30 from base 32

Design digit symbols for base 30 based on binary, starting with 2^5 = 32 characters and eliminating two characters.

Perhaps eliminate the two characters which correspond to the all zeroes bitstring and to the all ones bitstring, because they are so sparse or dense that they are difficult to distinguish from light or dark backgrounds.

Or, just eliminate the characters corresponding to 30 and 31.  Then the structure of digits could match their value.  Perhaps keep the character corresponding to 31 but assign it to zero.

Six-dot and eight-dot Braille already exist in Unicode.