Changed CSP packet id to network endian

[Rakagami]

In libcsp the Header ID is encoded as network/big-endian for csp 1 and csp 2.0:

Refer to:

• https://github.com/libcsp/libcsp/blob/6f81c3da04c051c35ed6c28612a4037c031bb1f3/src/csp_id.c#L42-L59
• https://github.com/libcsp/libcsp/blob/6f81c3da04c051c35ed6c28612a4037c031bb1f3/src/csp_id.c#L123-L141

[daniestevez]

The file python/csp_header.py is only used in some legacy code. We now have python/telemetry/csp.py, which uses construct and is used mostly everywhere.

I've checked where csp_header.py is still used, and saw the following:

• check_crc.py. This block is deprecated and will disappear.
• print_header.py. This block is deprecated and will disappear.
• swap_crc.py. This block isn't marked as deprecated, but it isn't used anywhere in gr-satellites.

The endianness of in csp.py was changed at some point because of #295. Your PR now changes csp_header.py to match the current state of csp.py, which seems good. Chances for breaking something else as a result of this change are slim, because csp_header.py isn't really used anywhere. Therefore, I'm happy to merge this PR, even though csp_header.py should be removed at some point. If you have code that is using csp_header.py, it probably makes sense to update it to use csp.py.

[Rakagami]

We are using print_header.py in our project which depended on csp_header.py. We will probably update to csp.py then if csp_header.py will be deleted anyway. What would you suggest as a replacement for print_header.py if we use csp.py?

[daniestevez]

It's possible to use the Telemetry Parser block with a telemetry definition of csp to replace print_header.py.

And now that I check, I see that the import for cspv2 is missing in __init__.py, so I'll go ahead and add this.