Remove "from foo import *" from packages

This is sloppy practice and at the end no one knows which names are actually in
a package. This breaks API for the last time.
Use correct imports for Spyder
Fix #203: Improve device class descriptions
Print help of parameters and quantities
Add help strings for base parameters
Set table size depending on number of term columns
Show state of device too
Add descriptions for detector and positioner
Split constructor and class docstring
Improve documentation