Add writing of .v3draw format for easy loading with Vaa3D.

Vaa3D (http://vaa3d.org ) is an open-source program for 3D
visualization and analysis of bioimage datasets.  .v3draw is a
minimalist format designed for rapid writing and reading with Vaa3D,
currently supported by Fiji for reading and writing.  This commit
provides .v3draw writing capability for bioformats.
Correct issues brought up by @melissalinkert

See pull request for content. Most substantive change: V3DrawWriter
class now takes endianness of file from metadata and writes the .v3draw
file  with the same byte order as the input.
Add PQBinReader for PicoQuant .bin files
Modfiy readers.txt to include PQBinReader
Correct HEADER_SIZE and add isThisType check.
Cosmetic changes as requested by rleigh.
Specify encoding when working with strings

This fixes warnings reported by Findbugs in
http://ci.openmicroscopy.org/view/Failing/job/BIOFORMATS-5.1-merge-build/352
Analyze: set littleEndian flag correctly

Fixes #12471.
Correct Reader in comment.
Remove unnecessary declaration of rowBuf.
Remove extra setting of m.littleendian.
Remove extra call to in.order.
Merge branch 'develop' of https://github.com/openmicroscopy/bioformats into develop-PQBin
Store pixelResolution as PixelsPhysicalSize
Untested changes to limit memory useage.
Add a size threshold to PQBinReader beyond which the data is not pre-loaded to obviate future memory issues. NB  loading is 4-5 times slower.
Add a similar size limit to SDTreader to obviate memory issues.
Set preLoad on closing.
Lower threshold to test both code paths.
Modify bfGetReader to setId() only on valid id

This is a breaking change in the behavior of bfGetReader. All the ui logic for
querying a valid path is now removed from the low-level function and should be
called upstream. A reader is always created but the `setId()` call is only
made if the input id is a valid file path or a fake string.