template: fold template() into __call__, minor optimizations - use non-grouping operator to avoid some extra processing - avoid copying and updating defaults - unnest main template body - avoid returning extra empty string if format

#!/bin/sh

mkdir t
cd t
hg init
echo a > a
hg add a
hg commit -m "test" -d "1000000 0"
hg verify
hg parents
hg status
hg rollback
hg verify
hg parents
hg status