CHG: Handling of comments in depth calibration files

[fhagemann]

Currently, comments in the depth spline files are used to pass information on DetID etc.
These comments should always start with three ### as denoted in their comments:

Comments in the depth splines file (we use this to pass the Detector ID, especially for files with multiple splines):

nuclearizer/src/MModuleDepthCalibration.cxx

Lines 736 to 739 in 3245f21

	// Input spline files should have the following format:
	// ### DetID, HV, Temperature, Photopeak Energy (TODO: More? Fewer?)
	// depth, ctd0, (optional) e_drift_times, (optional) h_drift_times
	// '' '' ''

Comments for the depth coefficients file (we use this to pass information about at which energy the timing resolution is quoted):

nuclearizer/src/MModuleDepthCalibration.cxx

Lines 650 to 653 in 3245f21

	// Read in the stretch and offset file, which should have a header line with information on the measurements:
	// ### 800 V 80 K 59.5 keV
	// And which should contain for each pixel:
	// Pixel code (10000*det + 100*LVStrip + HVStrip), Stretch, Offset, Timing/CTD noise in units of sigma, Chi2 for the CTD fit (for diagnostics mainly)

The way the nuclearizer code operates right now is that is parses EVERY line starting with # as a comment carrying that information. This does not allow us to put any other comments in the files, except for adding more tokens to these files.

Following the convention that will also be used in the charge trapping module in #184, I am proposing to explicitly search for ### for those comments carrying information, and to allow for single-# comments that will just be ignored.

[ckierans]

Nice easy convention. I like it. Once the checks have passed, feel free to merge.

[zoglauer]

The code looks OK.

[fhagemann]

Thanks for the swift responses!