support alternate data types in series binary loader
lazy evaluation of Images.dims property
remove hardcoded py4j version from thunder script
fix argument order in ImagesLoader.fromFile
fix typo in Data.collect method name
add data and tests for ImagesLoader
merge from upstream
change test resources dir getter to resolve from realpath of __file__
add lzw compressed tif test data
remove deflate-encoded tif test data
workaround for possible function argument serialization issue
Merge pull request #25 from industrial-sloth/custom-rdds

Custom rdds: support mixed data types in series loader, add image loader tests