Improvements to the template estimation (V, Vsky, Vpe)

1) Moves the actual estimation to external function since it is not
contingent on using the MCMC methods etc
2) Change notation to V, Vsky and Vpe
3) Fix some table outputs (Tcoh was forcing integer)
4) Rename of names -> detector_names
5) Adds tests
6) Writes a simpler table if the sky is not searched over