Add argdrop function
Added helper tests
acquire method added to dummy cameras
Acquisition concept added to experiments

The experiments now consist of smaller data acquisition
parts which improve modularity and thus reusability.
Added imaging acquisition routines

and classes for standard imaging experiments, such as
radiography and tomography. Helper functions for calculating
the desired paramters are added as well.
Experiment tests upgrade

Differ between experiment base tests and imaging based tests.
Test image acquisition routines as well as class behavior.
Experiment docs update