DTV_ — "General Concept" for "Time Axis" should be "Definition"

The glossary entry for Time Axis has a ‘General Concept:’ entry that reads “mathematical representation of the succession in time of instantaneous events along a unique axis”. The caption is wrong; it should be a ‘Definition:’.

Correct the caption in the ‘Time Axis’ glossary entry. Also, correct the wording of the definition to avoid the terms ‘representation’ and ‘instantaneous’ since the former could be confused with SBVR’s ‘representation’, and the latter is not true of the model we use.