NRRD: defer helper reader initialization

Instead of initializing the helper reader in setId (where we don't need
it), wait until openBytes is called for the first time.
Andor SIF: reduce the number of readLine() calls

This brings the setId time down to ~0.5s.
Varian: reduce the number of calls to readLine()

This brings the setId time under 0.5s.
Molecular Imaging: reduce the number of readLine() calls

setId time is now under 1s.
Zeiss CZI: reduce setId time for files with uncompressed images
InCell: setId performance improvements

In particular, reduce the number of loops over core.size(), and the
number of objects instantiated in said loops.
Leica LEI: improve setId performance

This primarily involves reading the entire .lei file into memory and
only calling list() when absolutely necessary.
Operetta: reduce setId execution time
CellWorX: minor setId performance improvements
CellR: reduce setId execution time
Canon RAW: reduce setId execution time
Leica: throw a nicer exception if TIFF files are not found
Remove debugging statement
CellR: fix path name tokenization on Windows

Noticed by Findbugs.
CellR: remove unnecessary call to TiffParser.fillInIFD

We don't need the filled-in IFD until openBytes is called, so there's no
need to call fillInIFD in setId.
FormatReader: speed up sanitization in calls to addMeta
POI: reduce the number of seeks
InCell: remove extraneous checks for metadata files

The currentId will already be the metadata file, so there is no need to
list the directory again to look for a metadata file.
Zeiss CZI: fix plane size calculation

This prevents an integer overflow/underflow when calculating the
expected plane size.
Canon: fix bit-shifting

...since bytes have 8 bits, not 16.