Those callback can be used by specific function type to allocate
and then free more memory than in raw usbg_function structure.
Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Adding support for a new function type was quite complicated.
Moreover the main library source fail was growing realy fast.
As a solution introduce internal OO API for defining function.
Thanks to this support for each function may be placed in
a separate file.
Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
