Kidney and visualization changes

[sarakurkowska]

Changes:

1. During initialization of biokinetics from previous cycles, when new lesions appear and no effective half-life is available from earlier cycles, the code uses all lesions from cycle 1 to calculate the mean effective half-life from lesions with a monoexponential fit. This may need to be adjusted in the future if more time points become available; for now, only monoexponential fitting is supported.
2. Minor changes were made to the report for better visualization.
3. The code was adjusted so that when kidneys are present, it does not require both the left and right kidney. Instead, it accepts any structure whose name starts with Kidney_, since some patients have only one kidney.
4. Added GE support in the DICOM tools for Q-SPECT calculations.