hgmerge: fix diff+patch detection; cleanups Details: - actually show help message when no tools are found - whitespace cleanup (stupid emacs) - quote more variables - simplify merge/diff3 error handling

#!/bin/sh

mkdir a
cd a
hg init
echo 123 > a
hg add a
hg commit -m "a" -u a -d "0 0"

cd ..
mkdir b
cd b
hg init
echo 321 > b
hg add b
hg commit -m "b" -u b -d "0 0"

hg pull ../a
hg heads