Add support for digital delay generator settings from sCMOS iStar

[irierr]

The following features from the iStar Feature Reference could be added:

Feature	Type	Description	Options
DDGIOCEnable	Boolean	Enable or disable the integrate on chip option.
DDGIOCNumberOfPulses	Integer	Configures the number of pulses generated when the integrate on chip option is enabled.
DDGIOCPeriod	Integer	Configures the period (in picoseconds) of the pulses generated when the integrate on chip option is enabled.
DDGOpticalWidthEnable	Boolean	Enable or disable the optical gate width option.
DDGOutputDelay	Integer	Configures the delay (in picoseconds) for the currently selected DDG output.
DDGOutputEnable	Boolean	Enable or disable the currently selected DDG output.
DDGOutputPolarity	Enumerated	Configures the polarity for the currently selected DDG output.	Negative, Positive
DDGOutputSelector	Enumerated	Selects the DDG output that you subsequently wish to configure using the DDG output Features.	Gater, Output A, Output B, Output C
DDGOutputStepEnable	Boolean	Enable or disable DDG step mode for the currently selected DDG output.
DDGOutputWidth	Integer	Configures the width (in picoseconds) for the currently selected DDG output.
DDGStepCount	Integer	Configures the number of frames that will use the same step value. If you are using accumulations and you require each of the accumulated frames to use the same step values then this feature should be set to the number of accumulations.
DDGStepDelayCoefficientA	Floating Point	Configures coefficient A for the delay DDG step.
DDGStepDelayCoefficientB	Floating Point	Configures coefficient B for the delay DDG step.
DDGStepDelayMode	Enumerated	Configures the delay DDG step mode.	Off, Constant, Exponential, Logarithmic
DDGStepEnabled	Boolean	Indicates when DDG step is enabled.
DDGStepUploadModeValues	Command	Uploads the DDG step values to the DDG frame buffer.
DDGStepUploadProgress	Integer	Indicates the current progess of the DDG step upload.
DDGStepUploadRequired	Boolean	Indicates if a DDG step upload is required.
DDGStepWidthCoefficientA	Floating Point	Configures coefficient A for the width DDG step.
DDGStepWidthCoefficientB	Floating Point	Configures coefficient B for the width DDG step.
DDGStepWidthMode	Enumerated	Configures the width DDG step mode.	Off, Constant, Exponential, Logarithmic

[irierr]

It would also be necessary to add the AOILayout feature to enable full use of the DDGStep... features.

Feature	Type	Description	Options
AOILayout	Enumerated		Image, Kinetics, TDI, Multitrack

[irierr]

I am working on this issue in my fork of the repo and should be done this month.