bugfix: on linux stats -c %B returns the block size while we expect a date here, changed to %B to %Y to get the last modified date
removed ending 'd' from tag names DateTimeOriginald and DateTimed, seems it is a typo error
Some EXIF contains zero date like 0000:00:00... Script was crashing in this case, FIX : detect zero date and fallback to next date detection method for all EXIF dates check.
Merge pull request #3 from cedricbou/master

Linux compatibility and EXIF data fixes.  Fixes #3
updated version of external exif-py library
run all files for exif data first (including RAW formats), then fall back on time stamp.  Fixes #5
added command line option to ignore exif entirely and just use file time stamp if desired
allow early morning photos to (optionally with command line argument) be grouped with the photos from the previous day.  Fixes #6.
fix for the day_begins option I just added.  previous method wouldn't work if the day was the first of the month. now it should be robust
updated readme
fix.  the day-begins argument was only applied to time stamp method, and is now also applied to exif method
Added sort by calendar week
Added some file extensions
Added file close to fix [Error 32].
If file is not closed, its not possible to move it. At least on Windows.
Merge branch 'kr2-master'
removed unnecessary import
more robust checking of valid EXIF timestamp
DateTimeOriginal should be checked before DateTimeDigitized
apparently the time data is optinal in EXIF datetime (http://www.w3.org/2003/12/exif/).  fixed parsing to handle exif data with only date info
Fix an array index out of range if an empty date is passed to valid_date