make sure temp folder hasn't been deleted since creation
don't try to log in if user cancels login dialog
allow changing case of profile name on Windows
Merge branch 'windows-case-fix'
update all duplicates when importing

If duplicate notes are already in the collection and, based on the first
field of all of them, they should be updated, update all of them instead
of just the first one we come across.
remove search text when ctrl-clicking a left panel item
fix rounding of cards/minute; use 1 decimal place
change default Anki folder location on Linux to Documents/Anki

(leave in ~/Anki for existing installs)