The public api is changed to require a context object for all
operations. Because other library objects store the context pointer
internally, only the constructor functions need an explicit context
object as a parameter.
Due to the use of the convenience functions, the device specific header
files are no longer necessary, and can be replaced with the high-level
header files.
Adding the "dc_" namespace prefix (which is of course an abbreviation
for libdivecomputer) should avoid conflicts with other libraries. For
the time being, only the high-level device and parser layers are
changed.
The public header files are moved to a new subdirectory, to separate
the definition of the public interface from the actual implementation.
Using an identical directory layout as the final installation has the
advantage that the example code can be build outside the project tree
without any modifications to the #include statements.
The Darwin and Darwin Air share a very similar layout, but with a few
differences here and there. Unfortunately, there seems to be no way to
autodetect the exact model during the download. Therefore, an extra
model parameter is added to select the appropriate model manually.
To be able to cancel an operation, an application should register a
callback function that returns a non-zero value whenever the active
operaton should be cancelled. A backend can invoke this callback function
to query the application for a pending cancellation request.
The handshake function is now called internally (even if it doesn't seem
to be required at all), and the version function can be called through
the public api. The format of the version data is changed too.
Using a resizable memory buffer allows to allocate the right amount of
memory inside the backend, avoiding having to know the required buffer
size in advance.
Although calibration is optional, it's highly recommended because it
reduces the transfer time considerably. The calibrate function is
removed from the public api.
