add git-foreach

Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com>
symexportcheck: read files manually

Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com>
git-stat: improve documentation

Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com>
threadsafetycheck: read files manually

Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com>