tests/test-tag

Modify commands.walk to yield a 4-tuple.
The new element of the tuple indicates whether a name is an exact match
for one passed in on the command line.

#!/bin/sh

hg init
echo a > a
hg add a
hg commit -m "test" -d "0 0"
hg history
hg tag -d "0 0" "bleah" 
hg history

echo foo >> .hgtags
hg tag -d "0 0" "bleah2" || echo "failed"