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 should allow us to work even with older chips. See the MPU6000
product specification, which says max 20MHz for sensor and interrupt
regs, and max 1MHz for all other regs
Gustavo Jose de Sousa
Randy Mackay
Andrew Tridgell
Pat Hickey