Fix availability and naming of properties and state structs for devices

[heliosfa]

This PR:

• Renames properties and state structures from the incorrect devtyp_{DEVICETYPE}_... format to {GRAPHTYPE}_{DEVICETYPE}_.... (fixes #231)
• Move the struct declarations to their own header, DeviceStructs.h, that is used by all devices and the Supervisor. (fixes #232)
• Adds #pragma pack(push,1) to the message stuct header. (partially addresses #240)
• Fixes a couple of issues in the apsp_vec_barrier_150_10.xml example that stoped it compiling.

The plate heat example has been updated, and a very simple compilation test added, in https://github.com/POETSII/Orchestrator_examples/pull/14.

Vol III B has had some minor updates: docx|pdf

APSP tweaks:

To get the APSP example to compile, I had to add #include <climits> to the shared code.

I also had to add a const unsigned cast to the second parameter in the calls to std::min to handle:

error: no matching function for call to 'min(const unsigned int&, long unsigned int)'
unsigned curr_k = std::min(K, graphProperties->total_vertices - deviceState->round_base);

There is still a warning that I am ignoring for now:

warning: comparison of integer expressions of different signedness: 'int32_t' {aka 'long int'} and 'unsigned int' [-Wsign-compare]
      if(0 <= id_delta && id_delta < K){

[heliosfa]

• Given that application writers are permitted to access these types (as this is a user-facing feature), I think they should be introduced in the application documentation, perhaps with a corresponding example handler 🍠.
• I think the application writer should be told that their message payloads are packed tightly - another documentation update perhaps?

I'll do a docs tweak and PR.

• Your APSP changes also seem sane, though I would suggest addressing the signedness warning (just use a cast in the condition?).

Interestingly, I now cannot reproduce this warning.

• Since you're fixing Types for device properties and state only available within that devices handlers #232, can we un-xfail the APSP test? These are denoted in the Bash scripts in Tests/ReferenceXML - they call TODO functions instead of success or failure functions. Do let me know if you need guidance with this. 🍠
• Where I put the 👍, I wondered if requestIdle had been implemented. If so, please "activate" the corresponding tests in the same way as the above. 🍠

I have enabled both of these tests.

[heliosfa]

Turns out that I had done the docs changes ages ago but forgot to PR them...