fixes spelling of பின்னு
updates trie creation fn
adds fn to split a string into constituent தமிழ் letters (and other non-Indic/non-complex l->r letters)
fixes tests, adds new ones
replaces map of quoted symbols with a quoted map of symbols for readability
adds sorting fns for letters (not chars!) and for words
organizes tests using nested testing forms
generalizes trie creation fns to enable values attached to input sequences
parameterizes input trie for str->letter splitter
adds sorting fns
adds char property and cursor pos util fns
adds tests to cover fns written up to now