Fixed an exception caused by the move of getWeekNumber into DateUtils.js

Since getWeekNumber has been moved into DateUtils and changed to accept
three parameters instead of one, this call was previously failing.
Partially restored the prior timeline dragging/date change behavior

Previously, dragging the timeline caused the calendar to change its date
based on the min time of the timeline, and didn't include momentum.  I
mostly just restored the code that was removed from TimelineTab.js in
commit c1888e76ff, with a few updates to match the new navigation
scheme.  I still have yet to implement code to ensure that navigating
away from and then back to the timeline tab keeps the timeline tab
bounds consistent.
Fixed "pinkish hue" bug with generating thumbnail from image with an alpha channel.  Fixed by discarding the alpha channel.  Also now forcing all thumbnails to be JPEGs.  This lets us safely assume that the MIME type for thumbnails is always image/jpeg, and we don't have to inspect the image to determine the type.  Thus, faster.
Disable the Picasa connector
Merge remote-tracking branch 'upstream/master'