Create include directory to help include namespaced header files

[NZSmartie]

Before the rebase in 0fa8289, I set my makefile to include the base folder which lobaro-coap was residing in. So my project's includes looked like:

#include "lobaro-coap/coap.h"

Namespacing the include files makes it easier when dealing multiple libraries or project file names that conflict.
In my case, esp-idf has included it's own own ported version of libcoap which I don't want to use. So #include "coap.h" could either mean libcoap's coap.h, or lobaro-coap's coap.h which my compiler isn't too happy about.

with the files now sitting under /src It would require me to create a symbolic link to fix the issue or maybe branch and rename the folder.

Instead I would like to propose that header files are moved to /include/lobaro-coap/ under the project root directory to help clean up potentially conflicting names.

[niondir]

What about using the library as a precompiled .a file and just reference the liblobaro_coap.h file which now contains most of the required public API?

It's possible after the api_refactoring. Anyway the only file you need now should be "liblobaro_coap.h" - we can move even more definitions there, it contains only the ones I needed yet.

[niondir]

As discussed in chat and my previous comment the issue is solved in a different way now. I don't think it's the end of header file refactoring yet but it's in a usable shape.