* use opaque algorithm interfaces
* add stream support

it caused runtime failures

Improved documentation and method comment to clarify that LineSegmentDetector::detect method accepts both Vec4i and Vec4f as return vector.

Let LineSegmentDetector output line segment coordinates in float precision, as supported by the LSD algorithm.

and unsynchronized.
Signed-off-by: Yan Wang <yan.wang@linux.intel.com>