QCoDeS/Qcodes: May 2019 release

Changelog for QCoDeS 0.3.0 The May 2019 release of QCoDeS contains a large backend re-structure of the Measurement.DataSaver logic as well a handful of driver improvements and some new data saving functionalities. New & Improved New and Improved Drivers: Alazar Cards: All models; limit maximum buffer size as documented for AlazarBeforeAsyncRead (#1535) All models; add api instance as initialization parameter (#1524) Arbitraty Waveform Generators: Keysight 33510B: add support for this specific model (#1544) Zurich Instruments HDAWG8; Remove warning when taking snapshot of ZIHDAWG8 (#1561) Lock-in Amplifiers: Zurich Instruments UHF-LI; support all 8 oscillators with MF option (#1546) Zurich Instruments UHF-LI; add parameter to UHFLI driver to select oscillator per demodulator (#1551) Magnets: American Magnetics AMI430; allow a broader range of field limit values (#1558) American Magnetics AMI430; fix coil-constant related bug (#1527) Multimeters: Tektronix Keithley 6500; allow immediate triggering (#1576) Tektronix Keithley 6500; fix invalid SCPI commands (#1541) Source Meters: Tektronix Keithley 2450; add brand new driver! (#1533, #1569) Vector Generators: Keysight E8267D; extend frequency modulation features (#1554) Vector Network Analyzers: Rohde&Schwarz ZNB; make initialization more fail-safe (#1564) Others: Mj2; allow higher gain (#1575) Cryocon; allow the setting of the termination character (#1559) Data Saving Features: Allow arrays of different lengths to be stored together (#1477) Allow complex numbers (#1484, #1489, #1493) Infer the SQLite storage type of parameters (#1494) Documentation: Increase title consistency (#1553) Database upgrades: Schema version bumped to 5; snapshot column always present (#1562) QCoDeS Workflow: Extend QCoDeS-Station to be configurable through yaml file (#1560) Breaking Changes The DataSet no longer has an add_parameter method (#1547) Miscellaneous The python package dependencies have been updated (#1550) Our copyright is up to date :) (#1552