Implementation

@kirienko @hickind @bondarv @schaffer

This implements the Keithley 6514 electrometer, a SCPI device over Landtronix. Here, the middlelayer SCPI api was used.

Originally, I wanted to have nodes, for the different measurement types, for which I added support in scpiML, but I'm now running low on time.
SQS requested a specific instantiation sequence that would, upon start-up, set the measurement mode to current, do zero-correction, and then set a slow integration rate. To do so, I added a sqsMode flag.

PS: I messed up the project creation, so there are tons of files, the only one that matters to review is src/Keithley6514/Keithley6514.py