fix(core): update load_experiment so that the runinfo.measured attribute has a list of the actual measured datasets

[mplilly4395]

Updated load_experiment.py to read datasets in the hdf5 file (which included measured data and generated data from scan0, ...) and load only the measured data in runinfo.measured.

tests were updated so this change to load_experiment did not lead to failed tests

closes #189

[mplilly4395]

I changed the function to find_measured_datasets. For the lists of datasets, all_datasets are the names of all of the datasets in the hdf5 file. These datasets are either datapoints measured in the measure_function (e.g. v1_readout) or they are datasets generated by the Experiment (e.g. v1_voltage, repeat, ...). I am using the local variable "generated" to keep track of this second list.