Keep track of frames that have missing sectors

[cjh1]

Keep track of frames that have missing sectors and write this information to HDF5 along with the counting data.

[ercius]

I think it would be useful to keep track of not only which probe positions are missing data, but also which sectors are missing in a given frame. An example of where this might be useful is when the top part of the detector can be ignored in some experimental geometry.

One way to do this is to use binary operations. I think there are 2^4 (16) different combinations of the four sectors. We can use binary to define if a sector has/has-not and data: '1111', '0111', '1010' etc.

For each sector that exists you bit-wise include a one and or everything together to produce a "loss value":
(int('0001',2) | int('0010',2)| int('0100',2) | int('1000',2))

Thus, all probe positions with this value == 15 have all sectors. Each unique number can be used to determine which sectors are lost for any given probe position with a "loss value" less than fifteen.