BUG: Scanline iterator in STAPLE filter not advanced to next line

An assert failed on debug build causing test failures. This detected
incorrect usage of the iterator where is was not being advanced to the
"NextLine" after each scanline.

Change-Id: I8e49ca9a37101f752fa68e05a1c865caf1ba6bd6
PERF: Use ImageScanlineIterator in ImageAlgorithm::Copy

Change-Id: I0c7ea3634916373072c16563ddfd7a4d29e13393
Merge topic 'ImageScanlineIteartorForImageCopy'

96e6e2e PERF: Use ImageScanlineIterator in ImageAlgorithm::Copy
Merge topic 'FixSTAPLEIteratorNextLine'

c71df8b BUG: Scanline iterator in STAPLE filter not advanced to next line