Unit of the injected data

[Yong2Sheng]

The the injected data has the unit of $cm^2/s/keV$. It should be None or cts.

I believe it's introduced by using tensor manipulation. It is an quick fix but I want to do it after merging current source injector PRs to avoid possible conflicts.

[israelmcmc]

Thanks @Yong2Sheng. Seems related to the discussion in PR #241. In particular, see the end of my comment here

[Yong2Sheng]

Thanks! @israelmcmc I will take a look at #241.