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.
This is a complete rewrite of the GPS driver structure, with a static
main driver and separate backend drivers. This will allow proper
support for multiple GPSes, and will allow parameters to be set on the
GPS object
Gustavo Jose de Sousa
Jonathan Challinger
Daniel Frenzel
Andrew Tridgell