Use the new simplified .command internally

This should be mostly backward compatible. One excepton is .match which
used _mad_command before.
Disable generation of unnecessary tempfiles

Also, change return type of Madx.match to not return the fit results
anymore, so it is independent of the filesystem as well. The new knob
values can be looked up with the Madx.evaluate method.
Remove obsolete functions in _madx_tools
Quote only 'file=' parameter