BUG: Respect drop-order of Pylon RAII object

[hirschenberger]

I sometimes git segfaults or aborts on application shutdowns from the pylon lib.

It happens when I store the Pylon object and InstantCamera object in other structures.

I found out that this happens because when dropping the InstantCamera struct, it's fields are dropped in declaration order and as Pylon is the first field, it's dropped and PylonTerminate call happens before the ffi::CInstantCamera object's destructor is called which causes the segfault.

The solution would simply be to change the field-order in InstantCamera.

[hirschenberger]

@astraw humble ping

[astraw]

Yes, sorry I've been very busy will try to get to this soon! Thanks for your patience.