docs: Prefer use of libusb_init_context() over old libusb_init()
- Replace some uses of the soft-deprecated libusb_init() and
libusb_set_debug() with their updates.
- Updated various comments to favour use of the new functions.
- Notably remove \deprecated doxygen statement, since it causes
-Wdocumentation compiler warnings.
- Notably update the xusb example to pass debug options to
libusb_init_context() instead of setting environment variable.
- Also improve comments related to LIBUSB_API_VERSION and
LIBUSBX_API_VERSION.
Closes #1408
[Tormod: Fix Doxygen formatting and references]
Signed-off-by: Tormod Volden <debian.tormod@gmail.com>
8 files changed
