Proper handling the input of polychromatic spectrum

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Current situation: (problems are bold)
Absorption (A) and Emission (E) intensities of the medium are given as vectors over a fixed range. The value are assumed to be equidistant inside the range.
The starting wavelength and the ending wavelength are hardcoded.
These intensity distributions are then sampled with a hardcoded sampling resolution.

Proposed solution:

• Assume both A and E are given for the same wavelength range
• Assume both A and E are sampled at the same wavelengths
• one vector to describe the sampling positions on the x-axis (wavelength)
• one vector for each A and E, to describe the intensities on the positions of the x-axis
• resample the distributions to ensure equidistant values and a sufficiently high resolution
• make the resolution a command line parameter (even better: find it automagically)

[slizzered]

yay closed!

[slizzered]

will remain open, until merged to master (milestone 1.5)