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.
Correct Reader in comment.
Remove unnecessary declaration of rowBuf.
Remove extra setting of m.littleendian.
Remove extra call to in.order.
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.
Merge pull request #1287 from sbesson/rebased/dev_5_0/develop-PQBin

Add reader for PicoQuant .bin files. (rebased onto dev_5_0)