Add LAC support

[mraspaud]

This PR adds support for LAC reading.

Hopefully it keeps the GAC reading untouched.

This supersedes and closes #5

[sfinkens]

Nice job! I didn't go through all the details, just two questions:

• The KLM readers don't have a scan_points attribute, is that correct?
• For POD, the scan_points array only has 408 elements, is that correct?
• That said, it would be nice if you could explain the meaning of scan_points and offset in the reader docstring :)

[mraspaud]

Good points, I'll check these

[mraspaud]

@sfinkens could this be a problem ?

[sfinkens]

Indeed, that's the reason!

[mraspaud]

So now we just have to decide if it's making the data better or not, right ? or should I just remove this ?

[mraspaud]

@sfinkens

1. scan_points is only used for computing new navigation points for the clock drift correction. So KLM shouldn't need them.

np.arange(3.5, 2048, 5).shape                                                                                                        
(409,)

?
Adding some documentation now

[sfinkens]

Sorry about the 408, I printed np.diff(np.arange(...)).shape, that's why it was one element shorter

[sfinkens]

System tests pass 👍