To be reverted once DOOCS with an eq_exit method has been released

Otherwise we run into a deadlock or random crashes

Follow-up fix for 32d3728c

It seems that setting up zmq might take longer than expected. Add
additional delay and move initial write after subscription to make sure
we really receive the inital event

Fixes #13

 - Introduce a new D_xy tag which takes x_source and y_source
 - The two sources are attached to a DataConsistentcyGroup. Only If the
   consistency group signalizes a consistent state, the data is updated

The change in test application causes FROM_DEVICE values to be written
only if the TO_DEVICE variables are modified.

Fixes #21

Fixes #21

It basically decorated the AutoPropertyDescription with the type which
is now in AutpPropertyDescription

Helps debugging a bit

Parse "type" attribute for normal properties

Bubble up the type to the parent class