Avoid using a delegator class

This shaves off about 20ms in Tobias Pietzsch' benchmark, down
from 1115ms.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
to-revert: did not bring any speed improvements

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Revert "to-revert: did not bring any speed improvements"

This reverts commit 7e52d94f5110ea1c2e409f13b3acef1d67eb9768.
Organize the imports in the ZeissTIFFReader

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Avoid using a delegating class in ZeissTIFFReader

This brings the time in Tobias' benchmark down to 957ms.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Make ZeissTIFFReader#isThisType() much more performant

It is inappropriate to invalidate the CaseInsensitiveLocation cache
every single time that the ZeissTIFFReader is run.

Additionally, this developer doubts that the implementation of the
insensitive location handling is sound. It should *at least* have a
look at the mtime of the directory (only evicting the cache if the
mtime has actually changed!). It should also *at least* try to find
the file in question with the given spelling, and only fall back to
enumerate the files in the same directory when the file was not found
with that spelling. It should never look into a directory whose path
displays different cases.

This single change brings the time of Tobias' benchmark down to 317ms
(from 957ms, no less).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>