Add automatic binary file detection to diff and export Based on a patch by Fuming Wang - add util.binary which decides whether a file is binary if it has any NUL characters in the first 1K. - teach mdiff.unidiff to print "binary file <x> has changed" for binary files - add text flag to cause unidiff and dodiff to treat all files as text - add -a and --text flags (like diff(1)) to hg diff and export - update docs