Offer to disable word-wrap for large files

[cowwoc]

The word-wrap feature has terrible performance for large files. I don't know at what point the performance problem begins, but opening a 200MB file with and without word-wrap shows a 10-100x performance difference.

I suggest one of two solutions:

1. Improve the performance of word-wrap, or
2. Detect when large files are being opened with word-wrap enabled and prompt the user whether he'd like to disable word-wrap before opening the file.