Make shtool a dependency, drop sudo in boostrap.sh

[vanrein]

I tried bootstrapping ksmppd and got a mild shock when it wanted to use sudo. This is not what you want scripts to do, unless you really make install -- it's a security loophole.

A workaround might be to install it in a subdirectory. But I found that treating shtool-dev as a dependency and commenting out the dangerous code also works. And it's not so wild to require dependencies.

Maybe a suggestion to make your code friendlier on new users who are exploring.