tests/test-merge3

keyword: pass context to kwtemplater.overwrite

Now that we have retrieved the context in every calling function
except commit, pass it as argument to kwtemplater.overwrite to
avoid looking it up twice.

Reorder arguments to kwtemplater.overwrite to reflect their
importance.

Turn node argument into a simple boolean and rename it to iswctx.

#!/bin/sh

hg init
echo This is file a1 > a
hg add a
hg commit -m "commit #0" -d "1000000 0"
touch b
hg add b
rm b
hg commit -A -m"comment #1" -d "1000000 0"
exit 0