Install parameters on instance instead of class

[MarcusZuber]

This should attach the parameters to the single instances and not to the class.

First tests are working:

from concert.devices.motors.dummy import LinearMotor
from concert.base import Quantity

l = await LinearMotor()
l2 = await LinearMotor()
l2.install_parameters({"pos2": Quantity(q.deg)})

l
<concert.devices.motors.dummy.LinearMotor object at 0x7f10a94d39a0>
 Parameter        Value                        
 motion_velocity  200000.0 millimeter / second 
 position         5 millimeter                 
 state            standby  

l2
<concert.devices.motors.dummy.LinearMotor object at 0x7f10a89d6fb0>
 Parameter        Value                        
 motion_velocity  200000.0 millimeter / second 
 pos2             N/A                          
 position         0 millimeter                 
 state            standby  

The actual use-case of this is, when employing different uca-cameras.
With the class-wide implementation, each of the concert.devices.camera.uca.Camera adds all plugin-parameters to the uca.Camera class.

[MarcusZuber]

@tfarago : Do you see any general problems here? I will also add a few tests for this later.

[tfarago]

What is the difference between setattr(self, 'foo', foo) and self.__dict__['foo'] = foo? You changed it to this kind and I am curious what the benefits are.