Make ConnectedComponent bitmap and hash lazy

ConnectedComponent's bitmap and hash values were being calculated on
construction, although ~95% were never accessed by Mser before
destruction. Instead, only calculate these members when requested.
Merge branch 'blockwise' of https://github.com/catsop/imageprocessing into blockwise

# By Andrew Champion
# Via Andrew Champion
* 'blockwise' of https://github.com/catsop/imageprocessing:
  Make ConnectedComponent bitmap and hash lazy