Add optimization to listdir to return filenames only
Merge branch 'master' of https://github.com/cbhaley/calibre
Merge branch 'master' of https://github.com/GRiker/calibre
Add an action to clear search history as well as disabling the popup
Move the filter text boxes to the top so that they are closer to the first result
Show the search expression for the virtual library in a tooltip when hovering over the tab for the virtual library. Fixes #1291691 [[Enhancement] VL search expression tooltip on hover](https://bugs.launchpad.net/calibre/+bug/1291691)
Edit book: Fix file permissions for the edited book being changed on Linux and OS X

Since the editor saves by using a temp file and then renaming the temp
file to overwrite the original, we have to explicitly copy over
permissions and owner metadata to the temp file to ensure they remain
unchanged.
Wireless device: Do not attempt to sync data when sending books for the first time.