added Jetty and Gson dependencies.
name Fetcher threads
remove unused field
make Hdf5ImageLoader methods getImageDimension() and existsImageData() public
BigDataServer and RemoteImageLoader
Merge branch 'janelia2' into remote
add getCache() to ViewerImgLoader interface
abstract base class for ViewerImgLoader implementations
MultiResolutionRenderer: actually use pre-allocated mask arrays...
pass re-usable ExecutorService to AccumulateProjector, and fix min/max bug
in calcuation of numTasks.
let ViewerImgLoader compute the mipmapTransforms.