Every backend stored a instance reference, which wasn't used in most locations
which is redundant given that the state already tracks the instance for us as
well.
This commit changes the way libraries headers are included in source files:
- If the header is in the same directory the source belongs to, so the
notation '#include ""' is used with the path relative to the directory
containing the source.
- If the header is outside the directory containing the source, then we use
the notation '#include <>' with the path relative to libraries folder.
Some of the advantages of such approach:
- Only one search path for libraries headers.
- OSs like Windows may have a better lookup time.
Andrew Tridgell
Michael du Breuil
Randy Mackay
Mathieu OTHACEHE
Lucas De Marchi
Gustavo Jose de Sousa
Jean-Baptiste Dubois