Implement NTTable to senv
Created by: SkyToGround
Description
This required more changes than I had initially thought. A general outline follows:
- Moved flatbuffer serialisation into classes to modularise the code.
- Removed serialisation of enums as strings to conform to the NeXus standard and the file-writer implementation.
- Changed responsibility for value extraction from ca/pva handlers to the serialisation code.
- Implemented conversion of (some specific) NTTables into senv flatbuffers.
On top of that I also had to implement some bug fixes and other minor improvements to make the tests run properly.