Memoizer: use Location instead of File to represent 'id'

This is consistent with other readers, in that it does not assume that
'id' is a file on disk.
Remove TODO
ScanR: clear the pixel buffer when an invalid TIFF is found
Merge pull request #506 from melissalinkert/memoizer-fixes

Memoizer: use Location instead of File to represent 'id'
SimplePCI: better calculation of Z/T dimensions

Conflicts:

	components/bio-formats/src/loci/formats/in/PCIReader.java
SimplePCI: do not populate more timestamps than planes
Merge pull request #518 from melissalinkert/rebased/develop/e283fb8e38042f5b0da2578e7c7fb07f838b92ca

ScanR: clear the pixel buffer when an invalid TIFF is found (rebased onto develop)
Merge pull request #519 from melissalinkert/cxd-dimensions-develop

.cxd dimension detection fixes (rebased onto develop)