Improve deallocation of GL context

Merge remote-tracking branch 'upstream/master'

Copy root window background

Merge remote-tracking branch 'upstream/master'

Bug fixes and upstream enchantments

Now i3lock-blur forks correctly when used with fuzzy option.
You can show the number of failed login attempts with switch -l.

Upgrade version number to match upstream

Fix important usability issue

Previous version used GLSL version 1.30.
Now it uses 1.20 so now it will work on more drivers.

Staying up with upstream

libX11 dependencies were removed from i3lock, but we still need them for
glX to work, and there is no libXCB alternative for joining GL and X.

Blurring is adjustable

With this release blurring is automatically adjusted for different
resolutions. Also there are new options (-r and -s) to manually adjust
blurring.

i3lock-blur 2.5.2

Now the unlock indicator size is not a fixed pixels amount.