File organization

[lhstrh]

As suggested by @Soroosh129, the ctarget.h file was put in include/ and ctarget.c was put in lib/. For the sake of consistency, we should probably split the files currently in core/ between include/core/ and lib/core/.

[Soroosh129]

I think core/include and core/lib might be better.

[lhstrh]

Your call entirely.

[lhstrh]

Following up on our conversation, here's a draft proposal for how to do this. Addressing this issue would be necessary ahead of #8 and might be a bit tricky. There is no rush with this effort, but let's make sure that we have a solid plan for doing this.
Here's what I gather so far. Feel free to go in and edit this:

core/include/platform.h
core/include/pqueue.h
...
core/lib/pqueue.c
core/lib/tag.c
...
core/platform/include/lf_C11_threads_support.h
...
federated/include/federate.h -> xronos/include/federate.h (i.e., later on move to separate xronos repo)
federated/lib/federate.c -> xronos/lib/federate.c
...
federated/include/rti.h -> xronos/include/rti.h
federated/lib/rti.c -> xronos/lib/rti.c
...