added threading to v4l2 capture
added env var 'VEEJAY_V4L2_ALL_IN_THREAD' (set to 1 to move all image processing into thread and memcpy the captured frame to consumer)
added env var 'VEEJAY_V4L2_MAX_RETRIES' (try before giving up)
added env var 'VEEJAY_V4L2_CAPTURE_METHOD' (set to 0 to use read/write interface)
poll before pull frame
changed default to threaded v4l2 capture
added support for jpeg based webcams such as sony eye toy
scan /sys/class/video4linux to find v4l devices or use dummy list (video0 to video7)
added function to see basic jpeg header to jpegutils, nothing fancy
added beta support for mjpeg based video devices (untested)