DataTools: close resource leak

Added a missing close() call when opening a new RandomAccessInputStream
for checking stream length. Should close this potential leak.
FormatTools - fixed Calibrate method name

Corrected case, renaming Calibrate -> calibrate.
ImageMetadata: never return 0 bits per pixel

If bitsPerPixel isn't manually set, use the FormatTools lookup based on
the current pixel type. Should reduce unnecessary code.
Metadata/ImageMetadata: expand size/planeSize API

Added a getPlaneSize method to ImageMetadata, and both getPlaneSize and
getSize (image size) to the Metadata interface, with implementations in
the abstract layer.