Implement the new AP_HAL functions and use them in the Scheduler when
possible.
The '_sketch_start_time' was renamed and moved as a detail of
implementation of the functions code. It allows the code to return time
starting from zero.
The 'stopped_clock_usec' was renamed to follow convention in the file
and add a getter so that AP_HAL functions can reach it. It's not a
problem this getter is public because in practice, regular code
shouldn't even access the SITLScheduler directly -- only code that
should is from SITL itself.
prog_char and prog_char_t are now the same as char on supported
platforms. So, just change all places that use them and prefer char
instead.
AVR-specific places were not changed.
Instead of just doing a static cast to the desired class, use a method
named "from". Pros:
- When we have data shared on the parent class, the code is cleaner in
child class when it needs to access this data. Almost all the data
we use in AP_HAL benefits from this
- There's a minimal type checking because now we are using a method
that can only receive the type of the parent class
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.