The new structure xine_current_frame_data_t additionally contains cropping
and interlacing information, which both are required for proper conversion
of the image. The existing functions have been adopted to use the code of
the new function. The changeset should be ABI compatible.

Here is a new video output plugin that passes raw data to the front end
through supplied callbacks.

--HG--
extra : transplant_source : -AT%2A%0A%EB%F5%1Eu4%9E%12%C4%B8%0B%87%13%A5%9D%CA

xine_get_current_frame() relies on the caller to provide a sufficiently
sized buffer. To calculate the required size of the buffer, one has to
call xine_get_current_frame() to retrieve the necessary parameters. But
as the image can change between two successive calls one has to pause
the stream for consistency.
To improve the situation, xine_get_current_frame_s() has been introduced
which requires to specify the buffer size when an image is going to be
retrieved. Furthermore, it will return the required/used buffer size.
In that way, it can prevent copying data into a too small buffer and
therefore can be considered safe.
For convenience, xine_get_current_frame_alloc() is provided which takes
care to allocate a sufficiently sized buffer. This function avoids
pausing the stream as the image will be returned in a single call.