Resolve "Detector: Add analysis unit test"

Closes #78

See merge request !27

Resolve "Source: Add analysis unit test"

Closes #77

See merge request !26

Resolve "EnergyMeter: Add analysis_inverse unit test"

Closes #79

See merge request !25

Fixed missing inverted() fn.

Resolve "Analysis: Improve error messages"

Closes #56

See merge request !24

code cleanup

Various code cleanups.

Resolve "OPOSSUM model file: Add version information"

Closes #54

See merge request !23

Resolve "OPOSSUM model file: Add version information"

Closes #54

See merge request !22

Resolve "Make OpticGraph a real struct"

Closes #71

See merge request !21

Add corresponding unit test.
Closes #66

Use OpmResult defined in error module.

Add general OpmResult typedef to error module.

Further code cleanup

code cleanup