Function: make-translation-table-from-alist

Make translation table from N<->M mapping in ALIST.
ALIST is an alist, each element has the form (FROM . TO).
FROM and TO are a character or a vector of characters.
If FROM is a character, that character is translated to TO.
If FROM is a vector of characters, that sequence is translated to TO.
The first extra-slot of the value is a translation table for reverse mapping.