Added function to test thread in use
Removed some debug output from Thread.cpp
Removed some other random debug stuff
Futher tidying after myself
- Removed debug print in `CMakeLists.txt`
- Added Node type enum
- Changed bool to int for `axeGetThreadInUse` for C compatability
- Added error handling for out-of-range nodeIDs to `axeGetNumNodes` and `axeGetNodeType`
- Removed un-implemented functions.
Matched enum order to other tools, and made names less likely to clash
Fixed arithmetic error, and made enums more clear - should also clear a warning on particular C++ compilers (according to stackoverflow)
Add Compiler flag `-fPIC`
This fixes an issue on `x86_64` machines where linking to `libaxe.a` would throw
```
relocation R_X86_64_32S against `.rodata' can not be used when making a shared object; recompile with -fPIC
```