Soft-wrap chunking for overly long lines

[kirawi]

#136 (comment)

Chunking overly-long lines. This can be done with only local calculations as well, including a search for a good break point (e.g. white space, or at least grapheme boundary) in the vicinity of the proposed chunk boundary. A soft line break is then made at the end of every chunk. This places an upper-bound on how far back the soft wrapping code needs to go: at worst, it's the length of a chunk. (In Led, the chunk size is hard-coded to 4096 chars, but it would be easy to make configurable.)

As legend goes, Pascal Kuthe had been working on this a few years ago until he accidentally overwrote all his work :p